INSTRUCTION stringlengths 1 8.43k | RESPONSE stringlengths 75 104k |
|---|---|
First discrete difference of element. | def diff(self, periods=1, axis=0):
"""
First discrete difference of element.
Calculates the difference of a DataFrame element compared with another
element in the DataFrame (default is the element in the same column
of the previous row).
Parameters
----------
periods : int, default 1
Periods to shift for calculating difference, accepts negative
values.
axis : {0 or 'index', 1 or 'columns'}, default 0
Take difference over rows (0) or columns (1).
.. versionadded:: 0.16.1.
Returns
-------
DataFrame
See Also
--------
Series.diff: First discrete difference for a Series.
DataFrame.pct_change: Percent change over given number of periods.
DataFrame.shift: Shift index by desired number of periods with an
optional time freq.
Examples
--------
Difference with previous row
>>> df = pd.DataFrame({'a': [1, 2, 3, 4, 5, 6],
... 'b': [1, 1, 2, 3, 5, 8],
... 'c': [1, 4, 9, 16, 25, 36]})
>>> df
a b c
0 1 1 1
1 2 1 4
2 3 2 9
3 4 3 16
4 5 5 25
5 6 8 36
>>> df.diff()
a b c
0 NaN NaN NaN
1 1.0 0.0 3.0
2 1.0 1.0 5.0
3 1.0 1.0 7.0
4 1.0 2.0 9.0
5 1.0 3.0 11.0
Difference with previous column
>>> df.diff(axis=1)
a b c
0 NaN 0.0 0.0
1 NaN -1.0 3.0
2 NaN -1.0 7.0
3 NaN -1.0 13.0
4 NaN 0.0 20.0
5 NaN 2.0 28.0
Difference with 3rd previous row
>>> df.diff(periods=3)
a b c
0 NaN NaN NaN
1 NaN NaN NaN
2 NaN NaN NaN
3 3.0 2.0 15.0
4 3.0 4.0 21.0
5 3.0 6.0 27.0
Difference with following row
>>> df.diff(periods=-1)
a b c
0 -1.0 0.0 -3.0
1 -1.0 -1.0 -5.0
2 -1.0 -1.0 -7.0
3 -1.0 -2.0 -9.0
4 -1.0 -3.0 -11.0
5 NaN NaN NaN
"""
bm_axis = self._get_block_manager_axis(axis)
new_data = self._data.diff(n=periods, axis=bm_axis)
return self._constructor(new_data) |
Sub - classes to define. Return a sliced object. | def _gotitem(self,
key: Union[str, List[str]],
ndim: int,
subset: Optional[Union[Series, ABCDataFrame]] = None,
) -> Union[Series, ABCDataFrame]:
"""
Sub-classes to define. Return a sliced object.
Parameters
----------
key : string / list of selections
ndim : 1,2
requested ndim of result
subset : object, default None
subset to act on
"""
if subset is None:
subset = self
elif subset.ndim == 1: # is Series
return subset
# TODO: _shallow_copy(subset)?
return subset[key] |
Apply a function along an axis of the DataFrame. | def apply(self, func, axis=0, broadcast=None, raw=False, reduce=None,
result_type=None, args=(), **kwds):
"""
Apply a function along an axis of the DataFrame.
Objects passed to the function are Series objects whose index is
either the DataFrame's index (``axis=0``) or the DataFrame's columns
(``axis=1``). By default (``result_type=None``), the final return type
is inferred from the return type of the applied function. Otherwise,
it depends on the `result_type` argument.
Parameters
----------
func : function
Function to apply to each column or row.
axis : {0 or 'index', 1 or 'columns'}, default 0
Axis along which the function is applied:
* 0 or 'index': apply function to each column.
* 1 or 'columns': apply function to each row.
broadcast : bool, optional
Only relevant for aggregation functions:
* ``False`` or ``None`` : returns a Series whose length is the
length of the index or the number of columns (based on the
`axis` parameter)
* ``True`` : results will be broadcast to the original shape
of the frame, the original index and columns will be retained.
.. deprecated:: 0.23.0
This argument will be removed in a future version, replaced
by result_type='broadcast'.
raw : bool, default False
* ``False`` : passes each row or column as a Series to the
function.
* ``True`` : the passed function will receive ndarray objects
instead.
If you are just applying a NumPy reduction function this will
achieve much better performance.
reduce : bool or None, default None
Try to apply reduction procedures. If the DataFrame is empty,
`apply` will use `reduce` to determine whether the result
should be a Series or a DataFrame. If ``reduce=None`` (the
default), `apply`'s return value will be guessed by calling
`func` on an empty Series
(note: while guessing, exceptions raised by `func` will be
ignored).
If ``reduce=True`` a Series will always be returned, and if
``reduce=False`` a DataFrame will always be returned.
.. deprecated:: 0.23.0
This argument will be removed in a future version, replaced
by ``result_type='reduce'``.
result_type : {'expand', 'reduce', 'broadcast', None}, default None
These only act when ``axis=1`` (columns):
* 'expand' : list-like results will be turned into columns.
* 'reduce' : returns a Series if possible rather than expanding
list-like results. This is the opposite of 'expand'.
* 'broadcast' : results will be broadcast to the original shape
of the DataFrame, the original index and columns will be
retained.
The default behaviour (None) depends on the return value of the
applied function: list-like results will be returned as a Series
of those. However if the apply function returns a Series these
are expanded to columns.
.. versionadded:: 0.23.0
args : tuple
Positional arguments to pass to `func` in addition to the
array/series.
**kwds
Additional keyword arguments to pass as keywords arguments to
`func`.
Returns
-------
Series or DataFrame
Result of applying ``func`` along the given axis of the
DataFrame.
See Also
--------
DataFrame.applymap: For elementwise operations.
DataFrame.aggregate: Only perform aggregating type operations.
DataFrame.transform: Only perform transforming type operations.
Notes
-----
In the current implementation apply calls `func` twice on the
first column/row to decide whether it can take a fast or slow
code path. This can lead to unexpected behavior if `func` has
side-effects, as they will take effect twice for the first
column/row.
Examples
--------
>>> df = pd.DataFrame([[4, 9]] * 3, columns=['A', 'B'])
>>> df
A B
0 4 9
1 4 9
2 4 9
Using a numpy universal function (in this case the same as
``np.sqrt(df)``):
>>> df.apply(np.sqrt)
A B
0 2.0 3.0
1 2.0 3.0
2 2.0 3.0
Using a reducing function on either axis
>>> df.apply(np.sum, axis=0)
A 12
B 27
dtype: int64
>>> df.apply(np.sum, axis=1)
0 13
1 13
2 13
dtype: int64
Retuning a list-like will result in a Series
>>> df.apply(lambda x: [1, 2], axis=1)
0 [1, 2]
1 [1, 2]
2 [1, 2]
dtype: object
Passing result_type='expand' will expand list-like results
to columns of a Dataframe
>>> df.apply(lambda x: [1, 2], axis=1, result_type='expand')
0 1
0 1 2
1 1 2
2 1 2
Returning a Series inside the function is similar to passing
``result_type='expand'``. The resulting column names
will be the Series index.
>>> df.apply(lambda x: pd.Series([1, 2], index=['foo', 'bar']), axis=1)
foo bar
0 1 2
1 1 2
2 1 2
Passing ``result_type='broadcast'`` will ensure the same shape
result, whether list-like or scalar is returned by the function,
and broadcast it along the axis. The resulting column names will
be the originals.
>>> df.apply(lambda x: [1, 2], axis=1, result_type='broadcast')
A B
0 1 2
1 1 2
2 1 2
"""
from pandas.core.apply import frame_apply
op = frame_apply(self,
func=func,
axis=axis,
broadcast=broadcast,
raw=raw,
reduce=reduce,
result_type=result_type,
args=args,
kwds=kwds)
return op.get_result() |
Apply a function to a Dataframe elementwise. | def applymap(self, func):
"""
Apply a function to a Dataframe elementwise.
This method applies a function that accepts and returns a scalar
to every element of a DataFrame.
Parameters
----------
func : callable
Python function, returns a single value from a single value.
Returns
-------
DataFrame
Transformed DataFrame.
See Also
--------
DataFrame.apply : Apply a function along input axis of DataFrame.
Notes
-----
In the current implementation applymap calls `func` twice on the
first column/row to decide whether it can take a fast or slow
code path. This can lead to unexpected behavior if `func` has
side-effects, as they will take effect twice for the first
column/row.
Examples
--------
>>> df = pd.DataFrame([[1, 2.12], [3.356, 4.567]])
>>> df
0 1
0 1.000 2.120
1 3.356 4.567
>>> df.applymap(lambda x: len(str(x)))
0 1
0 3 4
1 5 5
Note that a vectorized version of `func` often exists, which will
be much faster. You could square each number elementwise.
>>> df.applymap(lambda x: x**2)
0 1
0 1.000000 4.494400
1 11.262736 20.857489
But it's better to avoid applymap in that case.
>>> df ** 2
0 1
0 1.000000 4.494400
1 11.262736 20.857489
"""
# if we have a dtype == 'M8[ns]', provide boxed values
def infer(x):
if x.empty:
return lib.map_infer(x, func)
return lib.map_infer(x.astype(object).values, func)
return self.apply(infer) |
Append rows of other to the end of caller returning a new object. | def append(self, other, ignore_index=False,
verify_integrity=False, sort=None):
"""
Append rows of `other` to the end of caller, returning a new object.
Columns in `other` that are not in the caller are added as new columns.
Parameters
----------
other : DataFrame or Series/dict-like object, or list of these
The data to append.
ignore_index : boolean, default False
If True, do not use the index labels.
verify_integrity : boolean, default False
If True, raise ValueError on creating index with duplicates.
sort : boolean, default None
Sort columns if the columns of `self` and `other` are not aligned.
The default sorting is deprecated and will change to not-sorting
in a future version of pandas. Explicitly pass ``sort=True`` to
silence the warning and sort. Explicitly pass ``sort=False`` to
silence the warning and not sort.
.. versionadded:: 0.23.0
Returns
-------
DataFrame
See Also
--------
concat : General function to concatenate DataFrame, Series
or Panel objects.
Notes
-----
If a list of dict/series is passed and the keys are all contained in
the DataFrame's index, the order of the columns in the resulting
DataFrame will be unchanged.
Iteratively appending rows to a DataFrame can be more computationally
intensive than a single concatenate. A better solution is to append
those rows to a list and then concatenate the list with the original
DataFrame all at once.
Examples
--------
>>> df = pd.DataFrame([[1, 2], [3, 4]], columns=list('AB'))
>>> df
A B
0 1 2
1 3 4
>>> df2 = pd.DataFrame([[5, 6], [7, 8]], columns=list('AB'))
>>> df.append(df2)
A B
0 1 2
1 3 4
0 5 6
1 7 8
With `ignore_index` set to True:
>>> df.append(df2, ignore_index=True)
A B
0 1 2
1 3 4
2 5 6
3 7 8
The following, while not recommended methods for generating DataFrames,
show two ways to generate a DataFrame from multiple data sources.
Less efficient:
>>> df = pd.DataFrame(columns=['A'])
>>> for i in range(5):
... df = df.append({'A': i}, ignore_index=True)
>>> df
A
0 0
1 1
2 2
3 3
4 4
More efficient:
>>> pd.concat([pd.DataFrame([i], columns=['A']) for i in range(5)],
... ignore_index=True)
A
0 0
1 1
2 2
3 3
4 4
"""
if isinstance(other, (Series, dict)):
if isinstance(other, dict):
other = Series(other)
if other.name is None and not ignore_index:
raise TypeError('Can only append a Series if ignore_index=True'
' or if the Series has a name')
if other.name is None:
index = None
else:
# other must have the same index name as self, otherwise
# index name will be reset
index = Index([other.name], name=self.index.name)
idx_diff = other.index.difference(self.columns)
try:
combined_columns = self.columns.append(idx_diff)
except TypeError:
combined_columns = self.columns.astype(object).append(idx_diff)
other = other.reindex(combined_columns, copy=False)
other = DataFrame(other.values.reshape((1, len(other))),
index=index,
columns=combined_columns)
other = other._convert(datetime=True, timedelta=True)
if not self.columns.equals(combined_columns):
self = self.reindex(columns=combined_columns)
elif isinstance(other, list) and not isinstance(other[0], DataFrame):
other = DataFrame(other)
if (self.columns.get_indexer(other.columns) >= 0).all():
other = other.reindex(columns=self.columns)
from pandas.core.reshape.concat import concat
if isinstance(other, (list, tuple)):
to_concat = [self] + other
else:
to_concat = [self, other]
return concat(to_concat, ignore_index=ignore_index,
verify_integrity=verify_integrity,
sort=sort) |
Join columns of another DataFrame. | def join(self, other, on=None, how='left', lsuffix='', rsuffix='',
sort=False):
"""
Join columns of another DataFrame.
Join columns with `other` DataFrame either on index or on a key
column. Efficiently join multiple DataFrame objects by index at once by
passing a list.
Parameters
----------
other : DataFrame, Series, or list of DataFrame
Index should be similar to one of the columns in this one. If a
Series is passed, its name attribute must be set, and that will be
used as the column name in the resulting joined DataFrame.
on : str, list of str, or array-like, optional
Column or index level name(s) in the caller to join on the index
in `other`, otherwise joins index-on-index. If multiple
values given, the `other` DataFrame must have a MultiIndex. Can
pass an array as the join key if it is not already contained in
the calling DataFrame. Like an Excel VLOOKUP operation.
how : {'left', 'right', 'outer', 'inner'}, default 'left'
How to handle the operation of the two objects.
* left: use calling frame's index (or column if on is specified)
* right: use `other`'s index.
* outer: form union of calling frame's index (or column if on is
specified) with `other`'s index, and sort it.
lexicographically.
* inner: form intersection of calling frame's index (or column if
on is specified) with `other`'s index, preserving the order
of the calling's one.
lsuffix : str, default ''
Suffix to use from left frame's overlapping columns.
rsuffix : str, default ''
Suffix to use from right frame's overlapping columns.
sort : bool, default False
Order result DataFrame lexicographically by the join key. If False,
the order of the join key depends on the join type (how keyword).
Returns
-------
DataFrame
A dataframe containing columns from both the caller and `other`.
See Also
--------
DataFrame.merge : For column(s)-on-columns(s) operations.
Notes
-----
Parameters `on`, `lsuffix`, and `rsuffix` are not supported when
passing a list of `DataFrame` objects.
Support for specifying index levels as the `on` parameter was added
in version 0.23.0.
Examples
--------
>>> df = pd.DataFrame({'key': ['K0', 'K1', 'K2', 'K3', 'K4', 'K5'],
... 'A': ['A0', 'A1', 'A2', 'A3', 'A4', 'A5']})
>>> df
key A
0 K0 A0
1 K1 A1
2 K2 A2
3 K3 A3
4 K4 A4
5 K5 A5
>>> other = pd.DataFrame({'key': ['K0', 'K1', 'K2'],
... 'B': ['B0', 'B1', 'B2']})
>>> other
key B
0 K0 B0
1 K1 B1
2 K2 B2
Join DataFrames using their indexes.
>>> df.join(other, lsuffix='_caller', rsuffix='_other')
key_caller A key_other B
0 K0 A0 K0 B0
1 K1 A1 K1 B1
2 K2 A2 K2 B2
3 K3 A3 NaN NaN
4 K4 A4 NaN NaN
5 K5 A5 NaN NaN
If we want to join using the key columns, we need to set key to be
the index in both `df` and `other`. The joined DataFrame will have
key as its index.
>>> df.set_index('key').join(other.set_index('key'))
A B
key
K0 A0 B0
K1 A1 B1
K2 A2 B2
K3 A3 NaN
K4 A4 NaN
K5 A5 NaN
Another option to join using the key columns is to use the `on`
parameter. DataFrame.join always uses `other`'s index but we can use
any column in `df`. This method preserves the original DataFrame's
index in the result.
>>> df.join(other.set_index('key'), on='key')
key A B
0 K0 A0 B0
1 K1 A1 B1
2 K2 A2 B2
3 K3 A3 NaN
4 K4 A4 NaN
5 K5 A5 NaN
"""
# For SparseDataFrame's benefit
return self._join_compat(other, on=on, how=how, lsuffix=lsuffix,
rsuffix=rsuffix, sort=sort) |
Round a DataFrame to a variable number of decimal places. | def round(self, decimals=0, *args, **kwargs):
"""
Round a DataFrame to a variable number of decimal places.
Parameters
----------
decimals : int, dict, Series
Number of decimal places to round each column to. If an int is
given, round each column to the same number of places.
Otherwise dict and Series round to variable numbers of places.
Column names should be in the keys if `decimals` is a
dict-like, or in the index if `decimals` is a Series. Any
columns not included in `decimals` will be left as is. Elements
of `decimals` which are not columns of the input will be
ignored.
*args
Additional keywords have no effect but might be accepted for
compatibility with numpy.
**kwargs
Additional keywords have no effect but might be accepted for
compatibility with numpy.
Returns
-------
DataFrame
A DataFrame with the affected columns rounded to the specified
number of decimal places.
See Also
--------
numpy.around : Round a numpy array to the given number of decimals.
Series.round : Round a Series to the given number of decimals.
Examples
--------
>>> df = pd.DataFrame([(.21, .32), (.01, .67), (.66, .03), (.21, .18)],
... columns=['dogs', 'cats'])
>>> df
dogs cats
0 0.21 0.32
1 0.01 0.67
2 0.66 0.03
3 0.21 0.18
By providing an integer each column is rounded to the same number
of decimal places
>>> df.round(1)
dogs cats
0 0.2 0.3
1 0.0 0.7
2 0.7 0.0
3 0.2 0.2
With a dict, the number of places for specific columns can be
specfified with the column names as key and the number of decimal
places as value
>>> df.round({'dogs': 1, 'cats': 0})
dogs cats
0 0.2 0.0
1 0.0 1.0
2 0.7 0.0
3 0.2 0.0
Using a Series, the number of places for specific columns can be
specfified with the column names as index and the number of
decimal places as value
>>> decimals = pd.Series([0, 1], index=['cats', 'dogs'])
>>> df.round(decimals)
dogs cats
0 0.2 0.0
1 0.0 1.0
2 0.7 0.0
3 0.2 0.0
"""
from pandas.core.reshape.concat import concat
def _dict_round(df, decimals):
for col, vals in df.iteritems():
try:
yield _series_round(vals, decimals[col])
except KeyError:
yield vals
def _series_round(s, decimals):
if is_integer_dtype(s) or is_float_dtype(s):
return s.round(decimals)
return s
nv.validate_round(args, kwargs)
if isinstance(decimals, (dict, Series)):
if isinstance(decimals, Series):
if not decimals.index.is_unique:
raise ValueError("Index of decimals must be unique")
new_cols = [col for col in _dict_round(self, decimals)]
elif is_integer(decimals):
# Dispatch to Series.round
new_cols = [_series_round(v, decimals)
for _, v in self.iteritems()]
else:
raise TypeError("decimals must be an integer, a dict-like or a "
"Series")
if len(new_cols) > 0:
return self._constructor(concat(new_cols, axis=1),
index=self.index,
columns=self.columns)
else:
return self |
Compute pairwise correlation of columns excluding NA/ null values. | def corr(self, method='pearson', min_periods=1):
"""
Compute pairwise correlation of columns, excluding NA/null values.
Parameters
----------
method : {'pearson', 'kendall', 'spearman'} or callable
* pearson : standard correlation coefficient
* kendall : Kendall Tau correlation coefficient
* spearman : Spearman rank correlation
* callable: callable with input two 1d ndarrays
and returning a float. Note that the returned matrix from corr
will have 1 along the diagonals and will be symmetric
regardless of the callable's behavior
.. versionadded:: 0.24.0
min_periods : int, optional
Minimum number of observations required per pair of columns
to have a valid result. Currently only available for Pearson
and Spearman correlation.
Returns
-------
DataFrame
Correlation matrix.
See Also
--------
DataFrame.corrwith
Series.corr
Examples
--------
>>> def histogram_intersection(a, b):
... v = np.minimum(a, b).sum().round(decimals=1)
... return v
>>> df = pd.DataFrame([(.2, .3), (.0, .6), (.6, .0), (.2, .1)],
... columns=['dogs', 'cats'])
>>> df.corr(method=histogram_intersection)
dogs cats
dogs 1.0 0.3
cats 0.3 1.0
"""
numeric_df = self._get_numeric_data()
cols = numeric_df.columns
idx = cols.copy()
mat = numeric_df.values
if method == 'pearson':
correl = libalgos.nancorr(ensure_float64(mat), minp=min_periods)
elif method == 'spearman':
correl = libalgos.nancorr_spearman(ensure_float64(mat),
minp=min_periods)
elif method == 'kendall' or callable(method):
if min_periods is None:
min_periods = 1
mat = ensure_float64(mat).T
corrf = nanops.get_corr_func(method)
K = len(cols)
correl = np.empty((K, K), dtype=float)
mask = np.isfinite(mat)
for i, ac in enumerate(mat):
for j, bc in enumerate(mat):
if i > j:
continue
valid = mask[i] & mask[j]
if valid.sum() < min_periods:
c = np.nan
elif i == j:
c = 1.
elif not valid.all():
c = corrf(ac[valid], bc[valid])
else:
c = corrf(ac, bc)
correl[i, j] = c
correl[j, i] = c
else:
raise ValueError("method must be either 'pearson', "
"'spearman', 'kendall', or a callable, "
"'{method}' was supplied".format(method=method))
return self._constructor(correl, index=idx, columns=cols) |
Compute pairwise covariance of columns excluding NA/ null values. | def cov(self, min_periods=None):
"""
Compute pairwise covariance of columns, excluding NA/null values.
Compute the pairwise covariance among the series of a DataFrame.
The returned data frame is the `covariance matrix
<https://en.wikipedia.org/wiki/Covariance_matrix>`__ of the columns
of the DataFrame.
Both NA and null values are automatically excluded from the
calculation. (See the note below about bias from missing values.)
A threshold can be set for the minimum number of
observations for each value created. Comparisons with observations
below this threshold will be returned as ``NaN``.
This method is generally used for the analysis of time series data to
understand the relationship between different measures
across time.
Parameters
----------
min_periods : int, optional
Minimum number of observations required per pair of columns
to have a valid result.
Returns
-------
DataFrame
The covariance matrix of the series of the DataFrame.
See Also
--------
Series.cov : Compute covariance with another Series.
core.window.EWM.cov: Exponential weighted sample covariance.
core.window.Expanding.cov : Expanding sample covariance.
core.window.Rolling.cov : Rolling sample covariance.
Notes
-----
Returns the covariance matrix of the DataFrame's time series.
The covariance is normalized by N-1.
For DataFrames that have Series that are missing data (assuming that
data is `missing at random
<https://en.wikipedia.org/wiki/Missing_data#Missing_at_random>`__)
the returned covariance matrix will be an unbiased estimate
of the variance and covariance between the member Series.
However, for many applications this estimate may not be acceptable
because the estimate covariance matrix is not guaranteed to be positive
semi-definite. This could lead to estimate correlations having
absolute values which are greater than one, and/or a non-invertible
covariance matrix. See `Estimation of covariance matrices
<http://en.wikipedia.org/w/index.php?title=Estimation_of_covariance_
matrices>`__ for more details.
Examples
--------
>>> df = pd.DataFrame([(1, 2), (0, 3), (2, 0), (1, 1)],
... columns=['dogs', 'cats'])
>>> df.cov()
dogs cats
dogs 0.666667 -1.000000
cats -1.000000 1.666667
>>> np.random.seed(42)
>>> df = pd.DataFrame(np.random.randn(1000, 5),
... columns=['a', 'b', 'c', 'd', 'e'])
>>> df.cov()
a b c d e
a 0.998438 -0.020161 0.059277 -0.008943 0.014144
b -0.020161 1.059352 -0.008543 -0.024738 0.009826
c 0.059277 -0.008543 1.010670 -0.001486 -0.000271
d -0.008943 -0.024738 -0.001486 0.921297 -0.013692
e 0.014144 0.009826 -0.000271 -0.013692 0.977795
**Minimum number of periods**
This method also supports an optional ``min_periods`` keyword
that specifies the required minimum number of non-NA observations for
each column pair in order to have a valid result:
>>> np.random.seed(42)
>>> df = pd.DataFrame(np.random.randn(20, 3),
... columns=['a', 'b', 'c'])
>>> df.loc[df.index[:5], 'a'] = np.nan
>>> df.loc[df.index[5:10], 'b'] = np.nan
>>> df.cov(min_periods=12)
a b c
a 0.316741 NaN -0.150812
b NaN 1.248003 0.191417
c -0.150812 0.191417 0.895202
"""
numeric_df = self._get_numeric_data()
cols = numeric_df.columns
idx = cols.copy()
mat = numeric_df.values
if notna(mat).all():
if min_periods is not None and min_periods > len(mat):
baseCov = np.empty((mat.shape[1], mat.shape[1]))
baseCov.fill(np.nan)
else:
baseCov = np.cov(mat.T)
baseCov = baseCov.reshape((len(cols), len(cols)))
else:
baseCov = libalgos.nancorr(ensure_float64(mat), cov=True,
minp=min_periods)
return self._constructor(baseCov, index=idx, columns=cols) |
Compute pairwise correlation between rows or columns of DataFrame with rows or columns of Series or DataFrame. DataFrames are first aligned along both axes before computing the correlations. | def corrwith(self, other, axis=0, drop=False, method='pearson'):
"""
Compute pairwise correlation between rows or columns of DataFrame
with rows or columns of Series or DataFrame. DataFrames are first
aligned along both axes before computing the correlations.
Parameters
----------
other : DataFrame, Series
Object with which to compute correlations.
axis : {0 or 'index', 1 or 'columns'}, default 0
0 or 'index' to compute column-wise, 1 or 'columns' for row-wise.
drop : bool, default False
Drop missing indices from result.
method : {'pearson', 'kendall', 'spearman'} or callable
* pearson : standard correlation coefficient
* kendall : Kendall Tau correlation coefficient
* spearman : Spearman rank correlation
* callable: callable with input two 1d ndarrays
and returning a float
.. versionadded:: 0.24.0
Returns
-------
Series
Pairwise correlations.
See Also
-------
DataFrame.corr
"""
axis = self._get_axis_number(axis)
this = self._get_numeric_data()
if isinstance(other, Series):
return this.apply(lambda x: other.corr(x, method=method),
axis=axis)
other = other._get_numeric_data()
left, right = this.align(other, join='inner', copy=False)
if axis == 1:
left = left.T
right = right.T
if method == 'pearson':
# mask missing values
left = left + right * 0
right = right + left * 0
# demeaned data
ldem = left - left.mean()
rdem = right - right.mean()
num = (ldem * rdem).sum()
dom = (left.count() - 1) * left.std() * right.std()
correl = num / dom
elif method in ['kendall', 'spearman'] or callable(method):
def c(x):
return nanops.nancorr(x[0], x[1], method=method)
correl = Series(map(c,
zip(left.values.T, right.values.T)),
index=left.columns)
else:
raise ValueError("Invalid method {method} was passed, "
"valid methods are: 'pearson', 'kendall', "
"'spearman', or callable".
format(method=method))
if not drop:
# Find non-matching labels along the given axis
# and append missing correlations (GH 22375)
raxis = 1 if axis == 0 else 0
result_index = (this._get_axis(raxis).
union(other._get_axis(raxis)))
idx_diff = result_index.difference(correl.index)
if len(idx_diff) > 0:
correl = correl.append(Series([np.nan] * len(idx_diff),
index=idx_diff))
return correl |
Count non - NA cells for each column or row. | def count(self, axis=0, level=None, numeric_only=False):
"""
Count non-NA cells for each column or row.
The values `None`, `NaN`, `NaT`, and optionally `numpy.inf` (depending
on `pandas.options.mode.use_inf_as_na`) are considered NA.
Parameters
----------
axis : {0 or 'index', 1 or 'columns'}, default 0
If 0 or 'index' counts are generated for each column.
If 1 or 'columns' counts are generated for each **row**.
level : int or str, optional
If the axis is a `MultiIndex` (hierarchical), count along a
particular `level`, collapsing into a `DataFrame`.
A `str` specifies the level name.
numeric_only : bool, default False
Include only `float`, `int` or `boolean` data.
Returns
-------
Series or DataFrame
For each column/row the number of non-NA/null entries.
If `level` is specified returns a `DataFrame`.
See Also
--------
Series.count: Number of non-NA elements in a Series.
DataFrame.shape: Number of DataFrame rows and columns (including NA
elements).
DataFrame.isna: Boolean same-sized DataFrame showing places of NA
elements.
Examples
--------
Constructing DataFrame from a dictionary:
>>> df = pd.DataFrame({"Person":
... ["John", "Myla", "Lewis", "John", "Myla"],
... "Age": [24., np.nan, 21., 33, 26],
... "Single": [False, True, True, True, False]})
>>> df
Person Age Single
0 John 24.0 False
1 Myla NaN True
2 Lewis 21.0 True
3 John 33.0 True
4 Myla 26.0 False
Notice the uncounted NA values:
>>> df.count()
Person 5
Age 4
Single 5
dtype: int64
Counts for each **row**:
>>> df.count(axis='columns')
0 3
1 2
2 3
3 3
4 3
dtype: int64
Counts for one level of a `MultiIndex`:
>>> df.set_index(["Person", "Single"]).count(level="Person")
Age
Person
John 2
Lewis 1
Myla 1
"""
axis = self._get_axis_number(axis)
if level is not None:
return self._count_level(level, axis=axis,
numeric_only=numeric_only)
if numeric_only:
frame = self._get_numeric_data()
else:
frame = self
# GH #423
if len(frame._get_axis(axis)) == 0:
result = Series(0, index=frame._get_agg_axis(axis))
else:
if frame._is_mixed_type or frame._data.any_extension_types:
# the or any_extension_types is really only hit for single-
# column frames with an extension array
result = notna(frame).sum(axis=axis)
else:
# GH13407
series_counts = notna(frame).sum(axis=axis)
counts = series_counts.values
result = Series(counts, index=frame._get_agg_axis(axis))
return result.astype('int64') |
Count distinct observations over requested axis. | def nunique(self, axis=0, dropna=True):
"""
Count distinct observations over requested axis.
Return Series with number of distinct observations. Can ignore NaN
values.
.. versionadded:: 0.20.0
Parameters
----------
axis : {0 or 'index', 1 or 'columns'}, default 0
The axis to use. 0 or 'index' for row-wise, 1 or 'columns' for
column-wise.
dropna : bool, default True
Don't include NaN in the counts.
Returns
-------
Series
See Also
--------
Series.nunique: Method nunique for Series.
DataFrame.count: Count non-NA cells for each column or row.
Examples
--------
>>> df = pd.DataFrame({'A': [1, 2, 3], 'B': [1, 1, 1]})
>>> df.nunique()
A 3
B 1
dtype: int64
>>> df.nunique(axis=1)
0 1
1 2
2 2
dtype: int64
"""
return self.apply(Series.nunique, axis=axis, dropna=dropna) |
Return index of first occurrence of minimum over requested axis. NA/ null values are excluded. | def idxmin(self, axis=0, skipna=True):
"""
Return index of first occurrence of minimum over requested axis.
NA/null values are excluded.
Parameters
----------
axis : {0 or 'index', 1 or 'columns'}, default 0
0 or 'index' for row-wise, 1 or 'columns' for column-wise
skipna : boolean, default True
Exclude NA/null values. If an entire row/column is NA, the result
will be NA.
Returns
-------
Series
Indexes of minima along the specified axis.
Raises
------
ValueError
* If the row/column is empty
See Also
--------
Series.idxmin
Notes
-----
This method is the DataFrame version of ``ndarray.argmin``.
"""
axis = self._get_axis_number(axis)
indices = nanops.nanargmin(self.values, axis=axis, skipna=skipna)
index = self._get_axis(axis)
result = [index[i] if i >= 0 else np.nan for i in indices]
return Series(result, index=self._get_agg_axis(axis)) |
Let s be explicit about this. | def _get_agg_axis(self, axis_num):
"""
Let's be explicit about this.
"""
if axis_num == 0:
return self.columns
elif axis_num == 1:
return self.index
else:
raise ValueError('Axis must be 0 or 1 (got %r)' % axis_num) |
Get the mode ( s ) of each element along the selected axis. | def mode(self, axis=0, numeric_only=False, dropna=True):
"""
Get the mode(s) of each element along the selected axis.
The mode of a set of values is the value that appears most often.
It can be multiple values.
Parameters
----------
axis : {0 or 'index', 1 or 'columns'}, default 0
The axis to iterate over while searching for the mode:
* 0 or 'index' : get mode of each column
* 1 or 'columns' : get mode of each row
numeric_only : bool, default False
If True, only apply to numeric columns.
dropna : bool, default True
Don't consider counts of NaN/NaT.
.. versionadded:: 0.24.0
Returns
-------
DataFrame
The modes of each column or row.
See Also
--------
Series.mode : Return the highest frequency value in a Series.
Series.value_counts : Return the counts of values in a Series.
Examples
--------
>>> df = pd.DataFrame([('bird', 2, 2),
... ('mammal', 4, np.nan),
... ('arthropod', 8, 0),
... ('bird', 2, np.nan)],
... index=('falcon', 'horse', 'spider', 'ostrich'),
... columns=('species', 'legs', 'wings'))
>>> df
species legs wings
falcon bird 2 2.0
horse mammal 4 NaN
spider arthropod 8 0.0
ostrich bird 2 NaN
By default, missing values are not considered, and the mode of wings
are both 0 and 2. The second row of species and legs contains ``NaN``,
because they have only one mode, but the DataFrame has two rows.
>>> df.mode()
species legs wings
0 bird 2.0 0.0
1 NaN NaN 2.0
Setting ``dropna=False`` ``NaN`` values are considered and they can be
the mode (like for wings).
>>> df.mode(dropna=False)
species legs wings
0 bird 2 NaN
Setting ``numeric_only=True``, only the mode of numeric columns is
computed, and columns of other types are ignored.
>>> df.mode(numeric_only=True)
legs wings
0 2.0 0.0
1 NaN 2.0
To compute the mode over columns and not rows, use the axis parameter:
>>> df.mode(axis='columns', numeric_only=True)
0 1
falcon 2.0 NaN
horse 4.0 NaN
spider 0.0 8.0
ostrich 2.0 NaN
"""
data = self if not numeric_only else self._get_numeric_data()
def f(s):
return s.mode(dropna=dropna)
return data.apply(f, axis=axis) |
Return values at the given quantile over requested axis. | def quantile(self, q=0.5, axis=0, numeric_only=True,
interpolation='linear'):
"""
Return values at the given quantile over requested axis.
Parameters
----------
q : float or array-like, default 0.5 (50% quantile)
Value between 0 <= q <= 1, the quantile(s) to compute.
axis : {0, 1, 'index', 'columns'} (default 0)
Equals 0 or 'index' for row-wise, 1 or 'columns' for column-wise.
numeric_only : bool, default True
If False, the quantile of datetime and timedelta data will be
computed as well.
interpolation : {'linear', 'lower', 'higher', 'midpoint', 'nearest'}
This optional parameter specifies the interpolation method to use,
when the desired quantile lies between two data points `i` and `j`:
* linear: `i + (j - i) * fraction`, where `fraction` is the
fractional part of the index surrounded by `i` and `j`.
* lower: `i`.
* higher: `j`.
* nearest: `i` or `j` whichever is nearest.
* midpoint: (`i` + `j`) / 2.
.. versionadded:: 0.18.0
Returns
-------
Series or DataFrame
If ``q`` is an array, a DataFrame will be returned where the
index is ``q``, the columns are the columns of self, and the
values are the quantiles.
If ``q`` is a float, a Series will be returned where the
index is the columns of self and the values are the quantiles.
See Also
--------
core.window.Rolling.quantile: Rolling quantile.
numpy.percentile: Numpy function to compute the percentile.
Examples
--------
>>> df = pd.DataFrame(np.array([[1, 1], [2, 10], [3, 100], [4, 100]]),
... columns=['a', 'b'])
>>> df.quantile(.1)
a 1.3
b 3.7
Name: 0.1, dtype: float64
>>> df.quantile([.1, .5])
a b
0.1 1.3 3.7
0.5 2.5 55.0
Specifying `numeric_only=False` will also compute the quantile of
datetime and timedelta data.
>>> df = pd.DataFrame({'A': [1, 2],
... 'B': [pd.Timestamp('2010'),
... pd.Timestamp('2011')],
... 'C': [pd.Timedelta('1 days'),
... pd.Timedelta('2 days')]})
>>> df.quantile(0.5, numeric_only=False)
A 1.5
B 2010-07-02 12:00:00
C 1 days 12:00:00
Name: 0.5, dtype: object
"""
self._check_percentile(q)
data = self._get_numeric_data() if numeric_only else self
axis = self._get_axis_number(axis)
is_transposed = axis == 1
if is_transposed:
data = data.T
result = data._data.quantile(qs=q,
axis=1,
interpolation=interpolation,
transposed=is_transposed)
if result.ndim == 2:
result = self._constructor(result)
else:
result = self._constructor_sliced(result, name=q)
if is_transposed:
result = result.T
return result |
Cast to DatetimeIndex of timestamps at * beginning * of period. | def to_timestamp(self, freq=None, how='start', axis=0, copy=True):
"""
Cast to DatetimeIndex of timestamps, at *beginning* of period.
Parameters
----------
freq : str, default frequency of PeriodIndex
Desired frequency.
how : {'s', 'e', 'start', 'end'}
Convention for converting period to timestamp; start of period
vs. end.
axis : {0 or 'index', 1 or 'columns'}, default 0
The axis to convert (the index by default).
copy : bool, default True
If False then underlying input data is not copied.
Returns
-------
DataFrame with DatetimeIndex
"""
new_data = self._data
if copy:
new_data = new_data.copy()
axis = self._get_axis_number(axis)
if axis == 0:
new_data.set_axis(1, self.index.to_timestamp(freq=freq, how=how))
elif axis == 1:
new_data.set_axis(0, self.columns.to_timestamp(freq=freq, how=how))
else: # pragma: no cover
raise AssertionError('Axis must be 0 or 1. Got {ax!s}'.format(
ax=axis))
return self._constructor(new_data) |
Whether each element in the DataFrame is contained in values. | def isin(self, values):
"""
Whether each element in the DataFrame is contained in values.
Parameters
----------
values : iterable, Series, DataFrame or dict
The result will only be true at a location if all the
labels match. If `values` is a Series, that's the index. If
`values` is a dict, the keys must be the column names,
which must match. If `values` is a DataFrame,
then both the index and column labels must match.
Returns
-------
DataFrame
DataFrame of booleans showing whether each element in the DataFrame
is contained in values.
See Also
--------
DataFrame.eq: Equality test for DataFrame.
Series.isin: Equivalent method on Series.
Series.str.contains: Test if pattern or regex is contained within a
string of a Series or Index.
Examples
--------
>>> df = pd.DataFrame({'num_legs': [2, 4], 'num_wings': [2, 0]},
... index=['falcon', 'dog'])
>>> df
num_legs num_wings
falcon 2 2
dog 4 0
When ``values`` is a list check whether every value in the DataFrame
is present in the list (which animals have 0 or 2 legs or wings)
>>> df.isin([0, 2])
num_legs num_wings
falcon True True
dog False True
When ``values`` is a dict, we can pass values to check for each
column separately:
>>> df.isin({'num_wings': [0, 3]})
num_legs num_wings
falcon False False
dog False True
When ``values`` is a Series or DataFrame the index and column must
match. Note that 'falcon' does not match based on the number of legs
in df2.
>>> other = pd.DataFrame({'num_legs': [8, 2], 'num_wings': [0, 2]},
... index=['spider', 'falcon'])
>>> df.isin(other)
num_legs num_wings
falcon True True
dog False False
"""
if isinstance(values, dict):
from pandas.core.reshape.concat import concat
values = collections.defaultdict(list, values)
return concat((self.iloc[:, [i]].isin(values[col])
for i, col in enumerate(self.columns)), axis=1)
elif isinstance(values, Series):
if not values.index.is_unique:
raise ValueError("cannot compute isin with "
"a duplicate axis.")
return self.eq(values.reindex_like(self), axis='index')
elif isinstance(values, DataFrame):
if not (values.columns.is_unique and values.index.is_unique):
raise ValueError("cannot compute isin with "
"a duplicate axis.")
return self.eq(values.reindex_like(self))
else:
if not is_list_like(values):
raise TypeError("only list-like or dict-like objects are "
"allowed to be passed to DataFrame.isin(), "
"you passed a "
"{0!r}".format(type(values).__name__))
return DataFrame(
algorithms.isin(self.values.ravel(),
values).reshape(self.shape), self.index,
self.columns) |
Infer and return an integer array of the values. | def integer_array(values, dtype=None, copy=False):
"""
Infer and return an integer array of the values.
Parameters
----------
values : 1D list-like
dtype : dtype, optional
dtype to coerce
copy : boolean, default False
Returns
-------
IntegerArray
Raises
------
TypeError if incompatible types
"""
values, mask = coerce_to_array(values, dtype=dtype, copy=copy)
return IntegerArray(values, mask) |
Safely cast the values to the dtype if they are equivalent meaning floats must be equivalent to the ints. | def safe_cast(values, dtype, copy):
"""
Safely cast the values to the dtype if they
are equivalent, meaning floats must be equivalent to the
ints.
"""
try:
return values.astype(dtype, casting='safe', copy=copy)
except TypeError:
casted = values.astype(dtype, copy=copy)
if (casted == values).all():
return casted
raise TypeError("cannot safely cast non-equivalent {} to {}".format(
values.dtype, np.dtype(dtype))) |
Coerce the input values array to numpy arrays with a mask | def coerce_to_array(values, dtype, mask=None, copy=False):
"""
Coerce the input values array to numpy arrays with a mask
Parameters
----------
values : 1D list-like
dtype : integer dtype
mask : boolean 1D array, optional
copy : boolean, default False
if True, copy the input
Returns
-------
tuple of (values, mask)
"""
# if values is integer numpy array, preserve it's dtype
if dtype is None and hasattr(values, 'dtype'):
if is_integer_dtype(values.dtype):
dtype = values.dtype
if dtype is not None:
if (isinstance(dtype, str) and
(dtype.startswith("Int") or dtype.startswith("UInt"))):
# Avoid DeprecationWarning from NumPy about np.dtype("Int64")
# https://github.com/numpy/numpy/pull/7476
dtype = dtype.lower()
if not issubclass(type(dtype), _IntegerDtype):
try:
dtype = _dtypes[str(np.dtype(dtype))]
except KeyError:
raise ValueError("invalid dtype specified {}".format(dtype))
if isinstance(values, IntegerArray):
values, mask = values._data, values._mask
if dtype is not None:
values = values.astype(dtype.numpy_dtype, copy=False)
if copy:
values = values.copy()
mask = mask.copy()
return values, mask
values = np.array(values, copy=copy)
if is_object_dtype(values):
inferred_type = lib.infer_dtype(values, skipna=True)
if inferred_type == 'empty':
values = np.empty(len(values))
values.fill(np.nan)
elif inferred_type not in ['floating', 'integer',
'mixed-integer', 'mixed-integer-float']:
raise TypeError("{} cannot be converted to an IntegerDtype".format(
values.dtype))
elif not (is_integer_dtype(values) or is_float_dtype(values)):
raise TypeError("{} cannot be converted to an IntegerDtype".format(
values.dtype))
if mask is None:
mask = isna(values)
else:
assert len(mask) == len(values)
if not values.ndim == 1:
raise TypeError("values must be a 1D list-like")
if not mask.ndim == 1:
raise TypeError("mask must be a 1D list-like")
# infer dtype if needed
if dtype is None:
dtype = np.dtype('int64')
else:
dtype = dtype.type
# if we are float, let's make sure that we can
# safely cast
# we copy as need to coerce here
if mask.any():
values = values.copy()
values[mask] = 1
values = safe_cast(values, dtype, copy=False)
else:
values = safe_cast(values, dtype, copy=False)
return values, mask |
Construction from a string raise a TypeError if not possible | def construct_from_string(cls, string):
"""
Construction from a string, raise a TypeError if not
possible
"""
if string == cls.name:
return cls()
raise TypeError("Cannot construct a '{}' from "
"'{}'".format(cls, string)) |
coerce to an ndarary of object dtype | def _coerce_to_ndarray(self):
"""
coerce to an ndarary of object dtype
"""
# TODO(jreback) make this better
data = self._data.astype(object)
data[self._mask] = self._na_value
return data |
Cast to a NumPy array or IntegerArray with dtype. | def astype(self, dtype, copy=True):
"""
Cast to a NumPy array or IntegerArray with 'dtype'.
Parameters
----------
dtype : str or dtype
Typecode or data-type to which the array is cast.
copy : bool, default True
Whether to copy the data, even if not necessary. If False,
a copy is made only if the old dtype does not match the
new dtype.
Returns
-------
array : ndarray or IntegerArray
NumPy ndarray or IntergerArray with 'dtype' for its dtype.
Raises
------
TypeError
if incompatible type with an IntegerDtype, equivalent of same_kind
casting
"""
# if we are astyping to an existing IntegerDtype we can fastpath
if isinstance(dtype, _IntegerDtype):
result = self._data.astype(dtype.numpy_dtype, copy=False)
return type(self)(result, mask=self._mask, copy=False)
# coerce
data = self._coerce_to_ndarray()
return astype_nansafe(data, dtype, copy=None) |
Returns a Series containing counts of each category. | def value_counts(self, dropna=True):
"""
Returns a Series containing counts of each category.
Every category will have an entry, even those with a count of 0.
Parameters
----------
dropna : boolean, default True
Don't include counts of NaN.
Returns
-------
counts : Series
See Also
--------
Series.value_counts
"""
from pandas import Index, Series
# compute counts on the data with no nans
data = self._data[~self._mask]
value_counts = Index(data).value_counts()
array = value_counts.values
# TODO(extension)
# if we have allow Index to hold an ExtensionArray
# this is easier
index = value_counts.index.astype(object)
# if we want nans, count the mask
if not dropna:
# TODO(extension)
# appending to an Index *always* infers
# w/o passing the dtype
array = np.append(array, [self._mask.sum()])
index = Index(np.concatenate(
[index.values,
np.array([np.nan], dtype=object)]), dtype=object)
return Series(array, index=index) |
Return values for sorting. | def _values_for_argsort(self) -> np.ndarray:
"""Return values for sorting.
Returns
-------
ndarray
The transformed values should maintain the ordering between values
within the array.
See Also
--------
ExtensionArray.argsort
"""
data = self._data.copy()
data[self._mask] = data.min() - 1
return data |
Parameters ---------- result: array - like mask: array - like bool other: scalar or array - like op_name: str | def _maybe_mask_result(self, result, mask, other, op_name):
"""
Parameters
----------
result : array-like
mask : array-like bool
other : scalar or array-like
op_name : str
"""
# may need to fill infs
# and mask wraparound
if is_float_dtype(result):
mask |= (result == np.inf) | (result == -np.inf)
# if we have a float operand we are by-definition
# a float result
# or our op is a divide
if ((is_float_dtype(other) or is_float(other)) or
(op_name in ['rtruediv', 'truediv', 'rdiv', 'div'])):
result[mask] = np.nan
return result
return type(self)(result, mask, copy=False) |
return the length of a single non - tuple indexer which could be a slice | def length_of_indexer(indexer, target=None):
"""
return the length of a single non-tuple indexer which could be a slice
"""
if target is not None and isinstance(indexer, slice):
target_len = len(target)
start = indexer.start
stop = indexer.stop
step = indexer.step
if start is None:
start = 0
elif start < 0:
start += target_len
if stop is None or stop > target_len:
stop = target_len
elif stop < 0:
stop += target_len
if step is None:
step = 1
elif step < 0:
step = -step
return (stop - start + step - 1) // step
elif isinstance(indexer, (ABCSeries, Index, np.ndarray, list)):
return len(indexer)
elif not is_list_like_indexer(indexer):
return 1
raise AssertionError("cannot find the length of the indexer") |
if we are index sliceable then return my slicer otherwise return None | def convert_to_index_sliceable(obj, key):
"""
if we are index sliceable, then return my slicer, otherwise return None
"""
idx = obj.index
if isinstance(key, slice):
return idx._convert_slice_indexer(key, kind='getitem')
elif isinstance(key, str):
# we are an actual column
if obj._data.items.contains(key):
return None
# We might have a datetimelike string that we can translate to a
# slice here via partial string indexing
if idx.is_all_dates:
try:
return idx._get_string_slice(key)
except (KeyError, ValueError, NotImplementedError):
return None
return None |
Validate that value and indexer are the same length. | def check_setitem_lengths(indexer, value, values):
"""
Validate that value and indexer are the same length.
An special-case is allowed for when the indexer is a boolean array
and the number of true values equals the length of ``value``. In
this case, no exception is raised.
Parameters
----------
indexer : sequence
The key for the setitem
value : array-like
The value for the setitem
values : array-like
The values being set into
Returns
-------
None
Raises
------
ValueError
When the indexer is an ndarray or list and the lengths don't
match.
"""
# boolean with truth values == len of the value is ok too
if isinstance(indexer, (np.ndarray, list)):
if is_list_like(value) and len(indexer) != len(value):
if not (isinstance(indexer, np.ndarray) and
indexer.dtype == np.bool_ and
len(indexer[indexer]) == len(value)):
raise ValueError("cannot set using a list-like indexer "
"with a different length than the value")
# slice
elif isinstance(indexer, slice):
if is_list_like(value) and len(values):
if len(value) != length_of_indexer(indexer, values):
raise ValueError("cannot set using a slice indexer with a "
"different length than the value") |
reverse convert a missing indexer which is a dict return the scalar indexer and a boolean indicating if we converted | def convert_missing_indexer(indexer):
"""
reverse convert a missing indexer, which is a dict
return the scalar indexer and a boolean indicating if we converted
"""
if isinstance(indexer, dict):
# a missing key (but not a tuple indexer)
indexer = indexer['key']
if isinstance(indexer, bool):
raise KeyError("cannot use a single bool to index into setitem")
return indexer, True
return indexer, False |
create a filtered indexer that doesn t have any missing indexers | def convert_from_missing_indexer_tuple(indexer, axes):
"""
create a filtered indexer that doesn't have any missing indexers
"""
def get_indexer(_i, _idx):
return (axes[_i].get_loc(_idx['key']) if isinstance(_idx, dict) else
_idx)
return tuple(get_indexer(_i, _idx) for _i, _idx in enumerate(indexer)) |
Attempt to convert indices into valid positive indices. | def maybe_convert_indices(indices, n):
"""
Attempt to convert indices into valid, positive indices.
If we have negative indices, translate to positive here.
If we have indices that are out-of-bounds, raise an IndexError.
Parameters
----------
indices : array-like
The array of indices that we are to convert.
n : int
The number of elements in the array that we are indexing.
Returns
-------
valid_indices : array-like
An array-like of positive indices that correspond to the ones
that were passed in initially to this function.
Raises
------
IndexError : one of the converted indices either exceeded the number
of elements (specified by `n`) OR was still negative.
"""
if isinstance(indices, list):
indices = np.array(indices)
if len(indices) == 0:
# If list is empty, np.array will return float and cause indexing
# errors.
return np.empty(0, dtype=np.intp)
mask = indices < 0
if mask.any():
indices = indices.copy()
indices[mask] += n
mask = (indices >= n) | (indices < 0)
if mask.any():
raise IndexError("indices are out-of-bounds")
return indices |
Perform bounds - checking for an indexer. | def validate_indices(indices, n):
"""
Perform bounds-checking for an indexer.
-1 is allowed for indicating missing values.
Parameters
----------
indices : ndarray
n : int
length of the array being indexed
Raises
------
ValueError
Examples
--------
>>> validate_indices([1, 2], 3)
# OK
>>> validate_indices([1, -2], 3)
ValueError
>>> validate_indices([1, 2, 3], 3)
IndexError
>>> validate_indices([-1, -1], 0)
# OK
>>> validate_indices([0, 1], 0)
IndexError
"""
if len(indices):
min_idx = indices.min()
if min_idx < -1:
msg = ("'indices' contains values less than allowed ({} < {})"
.format(min_idx, -1))
raise ValueError(msg)
max_idx = indices.max()
if max_idx >= n:
raise IndexError("indices are out-of-bounds") |
We likely want to take the cross - product | def maybe_convert_ix(*args):
"""
We likely want to take the cross-product
"""
ixify = True
for arg in args:
if not isinstance(arg, (np.ndarray, list, ABCSeries, Index)):
ixify = False
if ixify:
return np.ix_(*args)
else:
return args |
Ensurse that a slice doesn t reduce to a Series or Scalar. | def _non_reducing_slice(slice_):
"""
Ensurse that a slice doesn't reduce to a Series or Scalar.
Any user-paseed `subset` should have this called on it
to make sure we're always working with DataFrames.
"""
# default to column slice, like DataFrame
# ['A', 'B'] -> IndexSlices[:, ['A', 'B']]
kinds = (ABCSeries, np.ndarray, Index, list, str)
if isinstance(slice_, kinds):
slice_ = IndexSlice[:, slice_]
def pred(part):
# true when slice does *not* reduce, False when part is a tuple,
# i.e. MultiIndex slice
return ((isinstance(part, slice) or is_list_like(part))
and not isinstance(part, tuple))
if not is_list_like(slice_):
if not isinstance(slice_, slice):
# a 1-d slice, like df.loc[1]
slice_ = [[slice_]]
else:
# slice(a, b, c)
slice_ = [slice_] # to tuplize later
else:
slice_ = [part if pred(part) else [part] for part in slice_]
return tuple(slice_) |
want nice defaults for background_gradient that don t break with non - numeric data. But if slice_ is passed go with that. | def _maybe_numeric_slice(df, slice_, include_bool=False):
"""
want nice defaults for background_gradient that don't break
with non-numeric data. But if slice_ is passed go with that.
"""
if slice_ is None:
dtypes = [np.number]
if include_bool:
dtypes.append(bool)
slice_ = IndexSlice[:, df.select_dtypes(include=dtypes).columns]
return slice_ |
check the key for valid keys across my indexer | def _has_valid_tuple(self, key):
""" check the key for valid keys across my indexer """
for i, k in enumerate(key):
if i >= self.obj.ndim:
raise IndexingError('Too many indexers')
try:
self._validate_key(k, i)
except ValueError:
raise ValueError("Location based indexing can only have "
"[{types}] types"
.format(types=self._valid_types)) |
validate that an positional indexer cannot enlarge its target will raise if needed does not modify the indexer externally | def _has_valid_positional_setitem_indexer(self, indexer):
""" validate that an positional indexer cannot enlarge its target
will raise if needed, does not modify the indexer externally
"""
if isinstance(indexer, dict):
raise IndexError("{0} cannot enlarge its target object"
.format(self.name))
else:
if not isinstance(indexer, tuple):
indexer = self._tuplify(indexer)
for ax, i in zip(self.obj.axes, indexer):
if isinstance(i, slice):
# should check the stop slice?
pass
elif is_list_like_indexer(i):
# should check the elements?
pass
elif is_integer(i):
if i >= len(ax):
raise IndexError("{name} cannot enlarge its target "
"object".format(name=self.name))
elif isinstance(i, dict):
raise IndexError("{name} cannot enlarge its target object"
.format(name=self.name))
return True |
Parameters ---------- indexer: tuple slice scalar The indexer used to get the locations that will be set to ser | def _align_series(self, indexer, ser, multiindex_indexer=False):
"""
Parameters
----------
indexer : tuple, slice, scalar
The indexer used to get the locations that will be set to
`ser`
ser : pd.Series
The values to assign to the locations specified by `indexer`
multiindex_indexer : boolean, optional
Defaults to False. Should be set to True if `indexer` was from
a `pd.MultiIndex`, to avoid unnecessary broadcasting.
Returns:
--------
`np.array` of `ser` broadcast to the appropriate shape for assignment
to the locations selected by `indexer`
"""
if isinstance(indexer, (slice, np.ndarray, list, Index)):
indexer = tuple([indexer])
if isinstance(indexer, tuple):
# flatten np.ndarray indexers
def ravel(i):
return i.ravel() if isinstance(i, np.ndarray) else i
indexer = tuple(map(ravel, indexer))
aligners = [not com.is_null_slice(idx) for idx in indexer]
sum_aligners = sum(aligners)
single_aligner = sum_aligners == 1
is_frame = self.obj.ndim == 2
is_panel = self.obj.ndim >= 3
obj = self.obj
# are we a single alignable value on a non-primary
# dim (e.g. panel: 1,2, or frame: 0) ?
# hence need to align to a single axis dimension
# rather that find all valid dims
# frame
if is_frame:
single_aligner = single_aligner and aligners[0]
# panel
elif is_panel:
single_aligner = (single_aligner and
(aligners[1] or aligners[2]))
# we have a frame, with multiple indexers on both axes; and a
# series, so need to broadcast (see GH5206)
if (sum_aligners == self.ndim and
all(is_sequence(_) for _ in indexer)):
ser = ser.reindex(obj.axes[0][indexer[0]], copy=True)._values
# single indexer
if len(indexer) > 1 and not multiindex_indexer:
len_indexer = len(indexer[1])
ser = np.tile(ser, len_indexer).reshape(len_indexer, -1).T
return ser
for i, idx in enumerate(indexer):
ax = obj.axes[i]
# multiple aligners (or null slices)
if is_sequence(idx) or isinstance(idx, slice):
if single_aligner and com.is_null_slice(idx):
continue
new_ix = ax[idx]
if not is_list_like_indexer(new_ix):
new_ix = Index([new_ix])
else:
new_ix = Index(new_ix)
if ser.index.equals(new_ix) or not len(new_ix):
return ser._values.copy()
return ser.reindex(new_ix)._values
# 2 dims
elif single_aligner and is_frame:
# reindex along index
ax = self.obj.axes[1]
if ser.index.equals(ax) or not len(ax):
return ser._values.copy()
return ser.reindex(ax)._values
# >2 dims
elif single_aligner:
broadcast = []
for n, labels in enumerate(self.obj._get_plane_axes(i)):
# reindex along the matching dimensions
if len(labels & ser.index):
ser = ser.reindex(labels)
else:
broadcast.append((n, len(labels)))
# broadcast along other dims
ser = ser._values.copy()
for (axis, l) in broadcast:
shape = [-1] * (len(broadcast) + 1)
shape[axis] = l
ser = np.tile(ser, l).reshape(shape)
if self.obj.ndim == 3:
ser = ser.T
return ser
elif is_scalar(indexer):
ax = self.obj._get_axis(1)
if ser.index.equals(ax):
return ser._values.copy()
return ser.reindex(ax)._values
raise ValueError('Incompatible indexer with Series') |
Check whether there is the possibility to use _multi_take. Currently the limit is that all axes being indexed must be indexed with list - likes. | def _multi_take_opportunity(self, tup):
"""
Check whether there is the possibility to use ``_multi_take``.
Currently the limit is that all axes being indexed must be indexed with
list-likes.
Parameters
----------
tup : tuple
Tuple of indexers, one per axis
Returns
-------
boolean: Whether the current indexing can be passed through _multi_take
"""
if not all(is_list_like_indexer(x) for x in tup):
return False
# just too complicated
if any(com.is_bool_indexer(x) for x in tup):
return False
return True |
Create the indexers for the passed tuple of keys and execute the take operation. This allows the take operation to be executed all at once - rather than once for each dimension - improving efficiency. | def _multi_take(self, tup):
"""
Create the indexers for the passed tuple of keys, and execute the take
operation. This allows the take operation to be executed all at once -
rather than once for each dimension - improving efficiency.
Parameters
----------
tup : tuple
Tuple of indexers, one per axis
Returns
-------
values: same type as the object being indexed
"""
# GH 836
o = self.obj
d = {axis: self._get_listlike_indexer(key, axis)
for (key, axis) in zip(tup, o._AXIS_ORDERS)}
return o._reindex_with_indexers(d, copy=True, allow_dups=True) |
Transform a list - like of keys into a new index and an indexer. | def _get_listlike_indexer(self, key, axis, raise_missing=False):
"""
Transform a list-like of keys into a new index and an indexer.
Parameters
----------
key : list-like
Target labels
axis: int
Dimension on which the indexing is being made
raise_missing: bool
Whether to raise a KeyError if some labels are not found. Will be
removed in the future, and then this method will always behave as
if raise_missing=True.
Raises
------
KeyError
If at least one key was requested but none was found, and
raise_missing=True.
Returns
-------
keyarr: Index
New index (coinciding with 'key' if the axis is unique)
values : array-like
An indexer for the return object; -1 denotes keys not found
"""
o = self.obj
ax = o._get_axis(axis)
# Have the index compute an indexer or return None
# if it cannot handle:
indexer, keyarr = ax._convert_listlike_indexer(key,
kind=self.name)
# We only act on all found values:
if indexer is not None and (indexer != -1).all():
self._validate_read_indexer(key, indexer, axis,
raise_missing=raise_missing)
return ax[indexer], indexer
if ax.is_unique:
# If we are trying to get actual keys from empty Series, we
# patiently wait for a KeyError later on - otherwise, convert
if len(ax) or not len(key):
key = self._convert_for_reindex(key, axis)
indexer = ax.get_indexer_for(key)
keyarr = ax.reindex(keyarr)[0]
else:
keyarr, indexer, new_indexer = ax._reindex_non_unique(keyarr)
self._validate_read_indexer(keyarr, indexer,
o._get_axis_number(axis),
raise_missing=raise_missing)
return keyarr, indexer |
Index current object with an an iterable key ( which can be a boolean indexer or a collection of keys ). | def _getitem_iterable(self, key, axis=None):
"""
Index current object with an an iterable key (which can be a boolean
indexer, or a collection of keys).
Parameters
----------
key : iterable
Target labels, or boolean indexer
axis: int, default None
Dimension on which the indexing is being made
Raises
------
KeyError
If no key was found. Will change in the future to raise if not all
keys were found.
IndexingError
If the boolean indexer is unalignable with the object being
indexed.
Returns
-------
scalar, DataFrame, or Series: indexed value(s),
"""
if axis is None:
axis = self.axis or 0
self._validate_key(key, axis)
labels = self.obj._get_axis(axis)
if com.is_bool_indexer(key):
# A boolean indexer
key = check_bool_indexer(labels, key)
inds, = key.nonzero()
return self.obj._take(inds, axis=axis)
else:
# A collection of keys
keyarr, indexer = self._get_listlike_indexer(key, axis,
raise_missing=False)
return self.obj._reindex_with_indexers({axis: [keyarr, indexer]},
copy=True, allow_dups=True) |
Check that indexer can be used to return a result ( e. g. at least one element was found unless the list of keys was actually empty ). | def _validate_read_indexer(self, key, indexer, axis, raise_missing=False):
"""
Check that indexer can be used to return a result (e.g. at least one
element was found, unless the list of keys was actually empty).
Parameters
----------
key : list-like
Target labels (only used to show correct error message)
indexer: array-like of booleans
Indices corresponding to the key (with -1 indicating not found)
axis: int
Dimension on which the indexing is being made
raise_missing: bool
Whether to raise a KeyError if some labels are not found. Will be
removed in the future, and then this method will always behave as
if raise_missing=True.
Raises
------
KeyError
If at least one key was requested but none was found, and
raise_missing=True.
"""
ax = self.obj._get_axis(axis)
if len(key) == 0:
return
# Count missing values:
missing = (indexer < 0).sum()
if missing:
if missing == len(indexer):
raise KeyError(
"None of [{key}] are in the [{axis}]".format(
key=key, axis=self.obj._get_axis_name(axis)))
# We (temporarily) allow for some missing keys with .loc, except in
# some cases (e.g. setting) in which "raise_missing" will be False
if not(self.name == 'loc' and not raise_missing):
not_found = list(set(key) - set(ax))
raise KeyError("{} not in index".format(not_found))
# we skip the warning on Categorical/Interval
# as this check is actually done (check for
# non-missing values), but a bit later in the
# code, so we want to avoid warning & then
# just raising
_missing_key_warning = textwrap.dedent("""
Passing list-likes to .loc or [] with any missing label will raise
KeyError in the future, you can use .reindex() as an alternative.
See the documentation here:
https://pandas.pydata.org/pandas-docs/stable/indexing.html#deprecate-loc-reindex-listlike""") # noqa
if not (ax.is_categorical() or ax.is_interval()):
warnings.warn(_missing_key_warning,
FutureWarning, stacklevel=6) |
Convert indexing key into something we can use to do actual fancy indexing on an ndarray | def _convert_to_indexer(self, obj, axis=None, is_setter=False,
raise_missing=False):
"""
Convert indexing key into something we can use to do actual fancy
indexing on an ndarray
Examples
ix[:5] -> slice(0, 5)
ix[[1,2,3]] -> [1,2,3]
ix[['foo', 'bar', 'baz']] -> [i, j, k] (indices of foo, bar, baz)
Going by Zen of Python?
'In the face of ambiguity, refuse the temptation to guess.'
raise AmbiguousIndexError with integer labels?
- No, prefer label-based indexing
"""
if axis is None:
axis = self.axis or 0
labels = self.obj._get_axis(axis)
if isinstance(obj, slice):
return self._convert_slice_indexer(obj, axis)
# try to find out correct indexer, if not type correct raise
try:
obj = self._convert_scalar_indexer(obj, axis)
except TypeError:
# but we will allow setting
if is_setter:
pass
# see if we are positional in nature
is_int_index = labels.is_integer()
is_int_positional = is_integer(obj) and not is_int_index
# if we are a label return me
try:
return labels.get_loc(obj)
except LookupError:
if isinstance(obj, tuple) and isinstance(labels, MultiIndex):
if is_setter and len(obj) == labels.nlevels:
return {'key': obj}
raise
except TypeError:
pass
except (ValueError):
if not is_int_positional:
raise
# a positional
if is_int_positional:
# if we are setting and its not a valid location
# its an insert which fails by definition
if is_setter:
# always valid
if self.name == 'loc':
return {'key': obj}
# a positional
if (obj >= self.obj.shape[axis] and
not isinstance(labels, MultiIndex)):
raise ValueError("cannot set by positional indexing with "
"enlargement")
return obj
if is_nested_tuple(obj, labels):
return labels.get_locs(obj)
elif is_list_like_indexer(obj):
if com.is_bool_indexer(obj):
obj = check_bool_indexer(labels, obj)
inds, = obj.nonzero()
return inds
else:
# When setting, missing keys are not allowed, even with .loc:
kwargs = {'raise_missing': True if is_setter else
raise_missing}
return self._get_listlike_indexer(obj, axis, **kwargs)[1]
else:
try:
return labels.get_loc(obj)
except LookupError:
# allow a not found key only if we are a setter
if not is_list_like_indexer(obj) and is_setter:
return {'key': obj}
raise |
Transform a list of keys into a new array ready to be used as axis of the object we return ( e. g. including NaNs ). | def _convert_for_reindex(self, key, axis=None):
"""
Transform a list of keys into a new array ready to be used as axis of
the object we return (e.g. including NaNs).
Parameters
----------
key : list-like
Target labels
axis: int
Where the indexing is being made
Returns
-------
list-like of labels
"""
if axis is None:
axis = self.axis or 0
labels = self.obj._get_axis(axis)
if com.is_bool_indexer(key):
key = check_bool_indexer(labels, key)
return labels[key]
if isinstance(key, Index):
keyarr = labels._convert_index_indexer(key)
else:
# asarray can be unsafe, NumPy strings are weird
keyarr = com.asarray_tuplesafe(key)
if is_integer_dtype(keyarr):
# Cast the indexer to uint64 if possible so
# that the values returned from indexing are
# also uint64.
keyarr = labels._convert_arr_indexer(keyarr)
if not labels.is_integer():
keyarr = ensure_platform_int(keyarr)
return labels.take(keyarr)
return keyarr |
this is pretty simple as we just have to deal with labels | def _get_slice_axis(self, slice_obj, axis=None):
""" this is pretty simple as we just have to deal with labels """
if axis is None:
axis = self.axis or 0
obj = self.obj
if not need_slice(slice_obj):
return obj.copy(deep=False)
labels = obj._get_axis(axis)
indexer = labels.slice_indexer(slice_obj.start, slice_obj.stop,
slice_obj.step, kind=self.name)
if isinstance(indexer, slice):
return self._slice(indexer, axis=axis, kind='iloc')
else:
return self.obj._take(indexer, axis=axis) |
Translate any partial string timestamp matches in key returning the new key ( GH 10331 ) | def _get_partial_string_timestamp_match_key(self, key, labels):
"""Translate any partial string timestamp matches in key, returning the
new key (GH 10331)"""
if isinstance(labels, MultiIndex):
if (isinstance(key, str) and labels.levels[0].is_all_dates):
# Convert key '2016-01-01' to
# ('2016-01-01'[, slice(None, None, None)]+)
key = tuple([key] + [slice(None)] * (len(labels.levels) - 1))
if isinstance(key, tuple):
# Convert (..., '2016-01-01', ...) in tuple to
# (..., slice('2016-01-01', '2016-01-01', None), ...)
new_key = []
for i, component in enumerate(key):
if (isinstance(component, str) and
labels.levels[i].is_all_dates):
new_key.append(slice(component, component, None))
else:
new_key.append(component)
key = tuple(new_key)
return key |
Check that key is a valid position in the desired axis. | def _validate_integer(self, key, axis):
"""
Check that 'key' is a valid position in the desired axis.
Parameters
----------
key : int
Requested position
axis : int
Desired axis
Returns
-------
None
Raises
------
IndexError
If 'key' is not a valid position in axis 'axis'
"""
len_axis = len(self.obj._get_axis(axis))
if key >= len_axis or key < -len_axis:
raise IndexError("single positional indexer is out-of-bounds") |
Return Series values by list or array of integers | def _get_list_axis(self, key, axis=None):
"""
Return Series values by list or array of integers
Parameters
----------
key : list-like positional indexer
axis : int (can only be zero)
Returns
-------
Series object
"""
if axis is None:
axis = self.axis or 0
try:
return self.obj._take(key, axis=axis)
except IndexError:
# re-raise with different error message
raise IndexError("positional indexers are out-of-bounds") |
much simpler as we only have to deal with our valid types | def _convert_to_indexer(self, obj, axis=None, is_setter=False):
""" much simpler as we only have to deal with our valid types """
if axis is None:
axis = self.axis or 0
# make need to convert a float key
if isinstance(obj, slice):
return self._convert_slice_indexer(obj, axis)
elif is_float(obj):
return self._convert_scalar_indexer(obj, axis)
try:
self._validate_key(obj, axis)
return obj
except ValueError:
raise ValueError("Can only index by location with "
"a [{types}]".format(types=self._valid_types)) |
require they keys to be the same type as the index ( so we don t fallback ) | def _convert_key(self, key, is_setter=False):
""" require they keys to be the same type as the index (so we don't
fallback)
"""
# allow arbitrary setting
if is_setter:
return list(key)
for ax, i in zip(self.obj.axes, key):
if ax.is_integer():
if not is_integer(i):
raise ValueError("At based indexing on an integer index "
"can only have integer indexers")
else:
if is_integer(i) and not ax.holds_integer():
raise ValueError("At based indexing on an non-integer "
"index can only have non-integer "
"indexers")
return key |
require integer args ( and convert to label arguments ) | def _convert_key(self, key, is_setter=False):
""" require integer args (and convert to label arguments) """
for a, i in zip(self.obj.axes, key):
if not is_integer(i):
raise ValueError("iAt based indexing can only have integer "
"indexers")
return key |
create and return the block manager from a dataframe of series columns index | def to_manager(sdf, columns, index):
""" create and return the block manager from a dataframe of series,
columns, index
"""
# from BlockManager perspective
axes = [ensure_index(columns), ensure_index(index)]
return create_block_manager_from_arrays(
[sdf[c] for c in columns], columns, axes) |
Only makes sense when fill_value is NaN | def stack_sparse_frame(frame):
"""
Only makes sense when fill_value is NaN
"""
lengths = [s.sp_index.npoints for _, s in frame.items()]
nobs = sum(lengths)
# this is pretty fast
minor_codes = np.repeat(np.arange(len(frame.columns)), lengths)
inds_to_concat = []
vals_to_concat = []
# TODO: Figure out whether this can be reached.
# I think this currently can't be reached because you can't build a
# SparseDataFrame with a non-np.NaN fill value (fails earlier).
for _, series in frame.items():
if not np.isnan(series.fill_value):
raise TypeError('This routine assumes NaN fill value')
int_index = series.sp_index.to_int_index()
inds_to_concat.append(int_index.indices)
vals_to_concat.append(series.sp_values)
major_codes = np.concatenate(inds_to_concat)
stacked_values = np.concatenate(vals_to_concat)
index = MultiIndex(levels=[frame.index, frame.columns],
codes=[major_codes, minor_codes],
verify_integrity=False)
lp = DataFrame(stacked_values.reshape((nobs, 1)), index=index,
columns=['foo'])
return lp.sort_index(level=0) |
Conform a set of SparseSeries ( with NaN fill_value ) to a common SparseIndex corresponding to the locations where they all have data | def homogenize(series_dict):
"""
Conform a set of SparseSeries (with NaN fill_value) to a common SparseIndex
corresponding to the locations where they all have data
Parameters
----------
series_dict : dict or DataFrame
Notes
-----
Using the dumbest algorithm I could think of. Should put some more thought
into this
Returns
-------
homogenized : dict of SparseSeries
"""
index = None
need_reindex = False
for _, series in series_dict.items():
if not np.isnan(series.fill_value):
raise TypeError('this method is only valid with NaN fill values')
if index is None:
index = series.sp_index
elif not series.sp_index.equals(index):
need_reindex = True
index = index.intersect(series.sp_index)
if need_reindex:
output = {}
for name, series in series_dict.items():
if not series.sp_index.equals(index):
series = series.sparse_reindex(index)
output[name] = series
else:
output = series_dict
return output |
Init self from ndarray or list of lists. | def _init_matrix(self, data, index, columns, dtype=None):
"""
Init self from ndarray or list of lists.
"""
data = prep_ndarray(data, copy=False)
index, columns = self._prep_index(data, index, columns)
data = {idx: data[:, i] for i, idx in enumerate(columns)}
return self._init_dict(data, index, columns, dtype) |
Init self from scipy. sparse matrix. | def _init_spmatrix(self, data, index, columns, dtype=None,
fill_value=None):
"""
Init self from scipy.sparse matrix.
"""
index, columns = self._prep_index(data, index, columns)
data = data.tocoo()
N = len(index)
# Construct a dict of SparseSeries
sdict = {}
values = Series(data.data, index=data.row, copy=False)
for col, rowvals in values.groupby(data.col):
# get_blocks expects int32 row indices in sorted order
rowvals = rowvals.sort_index()
rows = rowvals.index.values.astype(np.int32)
blocs, blens = get_blocks(rows)
sdict[columns[col]] = SparseSeries(
rowvals.values, index=index,
fill_value=fill_value,
sparse_index=BlockIndex(N, blocs, blens))
# Add any columns that were empty and thus not grouped on above
sdict.update({column: SparseSeries(index=index,
fill_value=fill_value,
sparse_index=BlockIndex(N, [], []))
for column in columns
if column not in sdict})
return self._init_dict(sdict, index, columns, dtype) |
Return the contents of the frame as a sparse SciPy COO matrix. | def to_coo(self):
"""
Return the contents of the frame as a sparse SciPy COO matrix.
.. versionadded:: 0.20.0
Returns
-------
coo_matrix : scipy.sparse.spmatrix
If the caller is heterogeneous and contains booleans or objects,
the result will be of dtype=object. See Notes.
Notes
-----
The dtype will be the lowest-common-denominator type (implicit
upcasting); that is to say if the dtypes (even of numeric types)
are mixed, the one that accommodates all will be chosen.
e.g. If the dtypes are float16 and float32, dtype will be upcast to
float32. By numpy.find_common_type convention, mixing int64 and
and uint64 will result in a float64 dtype.
"""
try:
from scipy.sparse import coo_matrix
except ImportError:
raise ImportError('Scipy is not installed')
dtype = find_common_type(self.dtypes)
if isinstance(dtype, SparseDtype):
dtype = dtype.subtype
cols, rows, datas = [], [], []
for col, name in enumerate(self):
s = self[name]
row = s.sp_index.to_int_index().indices
cols.append(np.repeat(col, len(row)))
rows.append(row)
datas.append(s.sp_values.astype(dtype, copy=False))
cols = np.concatenate(cols)
rows = np.concatenate(rows)
datas = np.concatenate(datas)
return coo_matrix((datas, (rows, cols)), shape=self.shape) |
Original pickle format | def _unpickle_sparse_frame_compat(self, state):
"""
Original pickle format
"""
series, cols, idx, fv, kind = state
if not isinstance(cols, Index): # pragma: no cover
from pandas.io.pickle import _unpickle_array
columns = _unpickle_array(cols)
else:
columns = cols
if not isinstance(idx, Index): # pragma: no cover
from pandas.io.pickle import _unpickle_array
index = _unpickle_array(idx)
else:
index = idx
series_dict = DataFrame()
for col, (sp_index, sp_values) in series.items():
series_dict[col] = SparseSeries(sp_values, sparse_index=sp_index,
fill_value=fv)
self._data = to_manager(series_dict, columns, index)
self._default_fill_value = fv
self._default_kind = kind |
Convert to dense DataFrame | def to_dense(self):
"""
Convert to dense DataFrame
Returns
-------
df : DataFrame
"""
data = {k: v.to_dense() for k, v in self.items()}
return DataFrame(data, index=self.index, columns=self.columns) |
Get new SparseDataFrame applying func to each columns | def _apply_columns(self, func):
"""
Get new SparseDataFrame applying func to each columns
"""
new_data = {col: func(series)
for col, series in self.items()}
return self._constructor(
data=new_data, index=self.index, columns=self.columns,
default_fill_value=self.default_fill_value).__finalize__(self) |
Make a copy of this SparseDataFrame | def copy(self, deep=True):
"""
Make a copy of this SparseDataFrame
"""
result = super().copy(deep=deep)
result._default_fill_value = self._default_fill_value
result._default_kind = self._default_kind
return result |
Ratio of non - sparse points to total ( dense ) data points represented in the frame | def density(self):
"""
Ratio of non-sparse points to total (dense) data points
represented in the frame
"""
tot_nonsparse = sum(ser.sp_index.npoints
for _, ser in self.items())
tot = len(self.index) * len(self.columns)
return tot_nonsparse / float(tot) |
Creates a new SparseArray from the input value. | def _sanitize_column(self, key, value, **kwargs):
"""
Creates a new SparseArray from the input value.
Parameters
----------
key : object
value : scalar, Series, or array-like
kwargs : dict
Returns
-------
sanitized_column : SparseArray
"""
def sp_maker(x, index=None):
return SparseArray(x, index=index,
fill_value=self._default_fill_value,
kind=self._default_kind)
if isinstance(value, SparseSeries):
clean = value.reindex(self.index).as_sparse_array(
fill_value=self._default_fill_value, kind=self._default_kind)
elif isinstance(value, SparseArray):
if len(value) != len(self.index):
raise ValueError('Length of values does not match '
'length of index')
clean = value
elif hasattr(value, '__iter__'):
if isinstance(value, Series):
clean = value.reindex(self.index)
if not isinstance(value, SparseSeries):
clean = sp_maker(clean)
else:
if len(value) != len(self.index):
raise ValueError('Length of values does not match '
'length of index')
clean = sp_maker(value)
# Scalar
else:
clean = sp_maker(value, self.index)
# always return a SparseArray!
return clean |
Returns a row ( cross - section ) from the SparseDataFrame as a Series object. | def xs(self, key, axis=0, copy=False):
"""
Returns a row (cross-section) from the SparseDataFrame as a Series
object.
Parameters
----------
key : some index contained in the index
Returns
-------
xs : Series
"""
if axis == 1:
data = self[key]
return data
i = self.index.get_loc(key)
data = self.take([i]).get_values()[0]
return Series(data, index=self.columns) |
Returns a DataFrame with the rows/ columns switched. | def transpose(self, *args, **kwargs):
"""
Returns a DataFrame with the rows/columns switched.
"""
nv.validate_transpose(args, kwargs)
return self._constructor(
self.values.T, index=self.columns, columns=self.index,
default_fill_value=self._default_fill_value,
default_kind=self._default_kind).__finalize__(self) |
Return SparseDataFrame of cumulative sums over requested axis. | def cumsum(self, axis=0, *args, **kwargs):
"""
Return SparseDataFrame of cumulative sums over requested axis.
Parameters
----------
axis : {0, 1}
0 for row-wise, 1 for column-wise
Returns
-------
y : SparseDataFrame
"""
nv.validate_cumsum(args, kwargs)
if axis is None:
axis = self._stat_axis_number
return self.apply(lambda x: x.cumsum(), axis=axis) |
Analogous to DataFrame. apply for SparseDataFrame | def apply(self, func, axis=0, broadcast=None, reduce=None,
result_type=None):
"""
Analogous to DataFrame.apply, for SparseDataFrame
Parameters
----------
func : function
Function to apply to each column
axis : {0, 1, 'index', 'columns'}
broadcast : bool, default False
For aggregation functions, return object of same size with values
propagated
.. deprecated:: 0.23.0
This argument will be removed in a future version, replaced
by result_type='broadcast'.
reduce : boolean or None, default None
Try to apply reduction procedures. If the DataFrame is empty,
apply will use reduce to determine whether the result should be a
Series or a DataFrame. If reduce is None (the default), apply's
return value will be guessed by calling func an empty Series (note:
while guessing, exceptions raised by func will be ignored). If
reduce is True a Series will always be returned, and if False a
DataFrame will always be returned.
.. deprecated:: 0.23.0
This argument will be removed in a future version, replaced
by result_type='reduce'.
result_type : {'expand', 'reduce', 'broadcast, None}
These only act when axis=1 {columns}:
* 'expand' : list-like results will be turned into columns.
* 'reduce' : return a Series if possible rather than expanding
list-like results. This is the opposite to 'expand'.
* 'broadcast' : results will be broadcast to the original shape
of the frame, the original index & columns will be retained.
The default behaviour (None) depends on the return value of the
applied function: list-like results will be returned as a Series
of those. However if the apply function returns a Series these
are expanded to columns.
.. versionadded:: 0.23.0
Returns
-------
applied : Series or SparseDataFrame
"""
if not len(self.columns):
return self
axis = self._get_axis_number(axis)
if isinstance(func, np.ufunc):
new_series = {}
for k, v in self.items():
applied = func(v)
applied.fill_value = func(v.fill_value)
new_series[k] = applied
return self._constructor(
new_series, index=self.index, columns=self.columns,
default_fill_value=self._default_fill_value,
default_kind=self._default_kind).__finalize__(self)
from pandas.core.apply import frame_apply
op = frame_apply(self,
func=func,
axis=axis,
reduce=reduce,
broadcast=broadcast,
result_type=result_type)
return op.get_result() |
Convert a conda package to its pip equivalent. | def conda_package_to_pip(package):
"""
Convert a conda package to its pip equivalent.
In most cases they are the same, those are the exceptions:
- Packages that should be excluded (in `EXCLUDE`)
- Packages that should be renamed (in `RENAME`)
- A package requiring a specific version, in conda is defined with a single
equal (e.g. ``pandas=1.0``) and in pip with two (e.g. ``pandas==1.0``)
"""
if package in EXCLUDE:
return
package = re.sub('(?<=[^<>])=', '==', package).strip()
for compare in ('<=', '>=', '=='):
if compare not in package:
continue
pkg, version = package.split(compare)
if pkg in RENAME:
return ''.join((RENAME[pkg], compare, version))
break
return package |
Generate the pip dependencies file from the conda file or compare that they are synchronized ( compare = True ). | def main(conda_fname, pip_fname, compare=False):
"""
Generate the pip dependencies file from the conda file, or compare that
they are synchronized (``compare=True``).
Parameters
----------
conda_fname : str
Path to the conda file with dependencies (e.g. `environment.yml`).
pip_fname : str
Path to the pip file with dependencies (e.g. `requirements-dev.txt`).
compare : bool, default False
Whether to generate the pip file (``False``) or to compare if the
pip file has been generated with this script and the last version
of the conda file (``True``).
Returns
-------
bool
True if the comparison fails, False otherwise
"""
with open(conda_fname) as conda_fd:
deps = yaml.safe_load(conda_fd)['dependencies']
pip_deps = []
for dep in deps:
if isinstance(dep, str):
conda_dep = conda_package_to_pip(dep)
if conda_dep:
pip_deps.append(conda_dep)
elif isinstance(dep, dict) and len(dep) == 1 and 'pip' in dep:
pip_deps += dep['pip']
else:
raise ValueError('Unexpected dependency {}'.format(dep))
pip_content = '\n'.join(pip_deps)
if compare:
with open(pip_fname) as pip_fd:
return pip_content != pip_fd.read()
else:
with open(pip_fname, 'w') as pip_fd:
pip_fd.write(pip_content)
return False |
try to do platform conversion allow ndarray or list here | def maybe_convert_platform(values):
""" try to do platform conversion, allow ndarray or list here """
if isinstance(values, (list, tuple)):
values = construct_1d_object_array_from_listlike(list(values))
if getattr(values, 'dtype', None) == np.object_:
if hasattr(values, '_values'):
values = values._values
values = lib.maybe_convert_objects(values)
return values |
return a boolean if we have a nested object e. g. a Series with 1 or more Series elements | def is_nested_object(obj):
"""
return a boolean if we have a nested object, e.g. a Series with 1 or
more Series elements
This may not be necessarily be performant.
"""
if isinstance(obj, ABCSeries) and is_object_dtype(obj):
if any(isinstance(v, ABCSeries) for v in obj.values):
return True
return False |
try to cast to the specified dtype ( e. g. convert back to bool/ int or could be an astype of float64 - > float32 | def maybe_downcast_to_dtype(result, dtype):
""" try to cast to the specified dtype (e.g. convert back to bool/int
or could be an astype of float64->float32
"""
if is_scalar(result):
return result
def trans(x):
return x
if isinstance(dtype, str):
if dtype == 'infer':
inferred_type = lib.infer_dtype(ensure_object(result.ravel()),
skipna=False)
if inferred_type == 'boolean':
dtype = 'bool'
elif inferred_type == 'integer':
dtype = 'int64'
elif inferred_type == 'datetime64':
dtype = 'datetime64[ns]'
elif inferred_type == 'timedelta64':
dtype = 'timedelta64[ns]'
# try to upcast here
elif inferred_type == 'floating':
dtype = 'int64'
if issubclass(result.dtype.type, np.number):
def trans(x): # noqa
return x.round()
else:
dtype = 'object'
if isinstance(dtype, str):
dtype = np.dtype(dtype)
try:
# don't allow upcasts here (except if empty)
if dtype.kind == result.dtype.kind:
if (result.dtype.itemsize <= dtype.itemsize and
np.prod(result.shape)):
return result
if is_bool_dtype(dtype) or is_integer_dtype(dtype):
# if we don't have any elements, just astype it
if not np.prod(result.shape):
return trans(result).astype(dtype)
# do a test on the first element, if it fails then we are done
r = result.ravel()
arr = np.array([r[0]])
# if we have any nulls, then we are done
if (isna(arr).any() or
not np.allclose(arr, trans(arr).astype(dtype), rtol=0)):
return result
# a comparable, e.g. a Decimal may slip in here
elif not isinstance(r[0], (np.integer, np.floating, np.bool, int,
float, bool)):
return result
if (issubclass(result.dtype.type, (np.object_, np.number)) and
notna(result).all()):
new_result = trans(result).astype(dtype)
try:
if np.allclose(new_result, result, rtol=0):
return new_result
except Exception:
# comparison of an object dtype with a number type could
# hit here
if (new_result == result).all():
return new_result
elif (issubclass(dtype.type, np.floating) and
not is_bool_dtype(result.dtype)):
return result.astype(dtype)
# a datetimelike
# GH12821, iNaT is casted to float
elif dtype.kind in ['M', 'm'] and result.dtype.kind in ['i', 'f']:
try:
result = result.astype(dtype)
except Exception:
if dtype.tz:
# convert to datetime and change timezone
from pandas import to_datetime
result = to_datetime(result).tz_localize('utc')
result = result.tz_convert(dtype.tz)
elif dtype.type == Period:
# TODO(DatetimeArray): merge with previous elif
from pandas.core.arrays import PeriodArray
return PeriodArray(result, freq=dtype.freq)
except Exception:
pass
return result |
A safe version of putmask that potentially upcasts the result. The result is replaced with the first N elements of other where N is the number of True values in mask. If the length of other is shorter than N other will be repeated. | def maybe_upcast_putmask(result, mask, other):
"""
A safe version of putmask that potentially upcasts the result.
The result is replaced with the first N elements of other,
where N is the number of True values in mask.
If the length of other is shorter than N, other will be repeated.
Parameters
----------
result : ndarray
The destination array. This will be mutated in-place if no upcasting is
necessary.
mask : boolean ndarray
other : ndarray or scalar
The source array or value
Returns
-------
result : ndarray
changed : boolean
Set to true if the result array was upcasted
Examples
--------
>>> result, _ = maybe_upcast_putmask(np.arange(1,6),
np.array([False, True, False, True, True]), np.arange(21,23))
>>> result
array([1, 21, 3, 22, 21])
"""
if not isinstance(result, np.ndarray):
raise ValueError("The result input must be a ndarray.")
if mask.any():
# Two conversions for date-like dtypes that can't be done automatically
# in np.place:
# NaN -> NaT
# integer or integer array -> date-like array
if is_datetimelike(result.dtype):
if is_scalar(other):
if isna(other):
other = result.dtype.type('nat')
elif is_integer(other):
other = np.array(other, dtype=result.dtype)
elif is_integer_dtype(other):
other = np.array(other, dtype=result.dtype)
def changeit():
# try to directly set by expanding our array to full
# length of the boolean
try:
om = other[mask]
om_at = om.astype(result.dtype)
if (om == om_at).all():
new_result = result.values.copy()
new_result[mask] = om_at
result[:] = new_result
return result, False
except Exception:
pass
# we are forced to change the dtype of the result as the input
# isn't compatible
r, _ = maybe_upcast(result, fill_value=other, copy=True)
np.place(r, mask, other)
return r, True
# we want to decide whether place will work
# if we have nans in the False portion of our mask then we need to
# upcast (possibly), otherwise we DON't want to upcast (e.g. if we
# have values, say integers, in the success portion then it's ok to not
# upcast)
new_dtype, _ = maybe_promote(result.dtype, other)
if new_dtype != result.dtype:
# we have a scalar or len 0 ndarray
# and its nan and we are changing some values
if (is_scalar(other) or
(isinstance(other, np.ndarray) and other.ndim < 1)):
if isna(other):
return changeit()
# we have an ndarray and the masking has nans in it
else:
if isna(other).any():
return changeit()
try:
np.place(result, mask, other)
except Exception:
return changeit()
return result, False |
interpret the dtype from a scalar or array. This is a convenience routines to infer dtype from a scalar or an array | def infer_dtype_from(val, pandas_dtype=False):
"""
interpret the dtype from a scalar or array. This is a convenience
routines to infer dtype from a scalar or an array
Parameters
----------
pandas_dtype : bool, default False
whether to infer dtype including pandas extension types.
If False, scalar/array belongs to pandas extension types is inferred as
object
"""
if is_scalar(val):
return infer_dtype_from_scalar(val, pandas_dtype=pandas_dtype)
return infer_dtype_from_array(val, pandas_dtype=pandas_dtype) |
interpret the dtype from a scalar | def infer_dtype_from_scalar(val, pandas_dtype=False):
"""
interpret the dtype from a scalar
Parameters
----------
pandas_dtype : bool, default False
whether to infer dtype including pandas extension types.
If False, scalar belongs to pandas extension types is inferred as
object
"""
dtype = np.object_
# a 1-element ndarray
if isinstance(val, np.ndarray):
msg = "invalid ndarray passed to infer_dtype_from_scalar"
if val.ndim != 0:
raise ValueError(msg)
dtype = val.dtype
val = val.item()
elif isinstance(val, str):
# If we create an empty array using a string to infer
# the dtype, NumPy will only allocate one character per entry
# so this is kind of bad. Alternately we could use np.repeat
# instead of np.empty (but then you still don't want things
# coming out as np.str_!
dtype = np.object_
elif isinstance(val, (np.datetime64, datetime)):
val = tslibs.Timestamp(val)
if val is tslibs.NaT or val.tz is None:
dtype = np.dtype('M8[ns]')
else:
if pandas_dtype:
dtype = DatetimeTZDtype(unit='ns', tz=val.tz)
else:
# return datetimetz as object
return np.object_, val
val = val.value
elif isinstance(val, (np.timedelta64, timedelta)):
val = tslibs.Timedelta(val).value
dtype = np.dtype('m8[ns]')
elif is_bool(val):
dtype = np.bool_
elif is_integer(val):
if isinstance(val, np.integer):
dtype = type(val)
else:
dtype = np.int64
elif is_float(val):
if isinstance(val, np.floating):
dtype = type(val)
else:
dtype = np.float64
elif is_complex(val):
dtype = np.complex_
elif pandas_dtype:
if lib.is_period(val):
dtype = PeriodDtype(freq=val.freq)
val = val.ordinal
return dtype, val |
infer the dtype from a scalar or array | def infer_dtype_from_array(arr, pandas_dtype=False):
"""
infer the dtype from a scalar or array
Parameters
----------
arr : scalar or array
pandas_dtype : bool, default False
whether to infer dtype including pandas extension types.
If False, array belongs to pandas extension types
is inferred as object
Returns
-------
tuple (numpy-compat/pandas-compat dtype, array)
Notes
-----
if pandas_dtype=False. these infer to numpy dtypes
exactly with the exception that mixed / object dtypes
are not coerced by stringifying or conversion
if pandas_dtype=True. datetime64tz-aware/categorical
types will retain there character.
Examples
--------
>>> np.asarray([1, '1'])
array(['1', '1'], dtype='<U21')
>>> infer_dtype_from_array([1, '1'])
(numpy.object_, [1, '1'])
"""
if isinstance(arr, np.ndarray):
return arr.dtype, arr
if not is_list_like(arr):
arr = [arr]
if pandas_dtype and is_extension_type(arr):
return arr.dtype, arr
elif isinstance(arr, ABCSeries):
return arr.dtype, np.asarray(arr)
# don't force numpy coerce with nan's
inferred = lib.infer_dtype(arr, skipna=False)
if inferred in ['string', 'bytes', 'unicode',
'mixed', 'mixed-integer']:
return (np.object_, arr)
arr = np.asarray(arr)
return arr.dtype, arr |
Try to infer an object s dtype for use in arithmetic ops | def maybe_infer_dtype_type(element):
"""Try to infer an object's dtype, for use in arithmetic ops
Uses `element.dtype` if that's available.
Objects implementing the iterator protocol are cast to a NumPy array,
and from there the array's type is used.
Parameters
----------
element : object
Possibly has a `.dtype` attribute, and possibly the iterator
protocol.
Returns
-------
tipo : type
Examples
--------
>>> from collections import namedtuple
>>> Foo = namedtuple("Foo", "dtype")
>>> maybe_infer_dtype_type(Foo(np.dtype("i8")))
numpy.int64
"""
tipo = None
if hasattr(element, 'dtype'):
tipo = element.dtype
elif is_list_like(element):
element = np.asarray(element)
tipo = element.dtype
return tipo |
provide explicit type promotion and coercion | def maybe_upcast(values, fill_value=np.nan, dtype=None, copy=False):
""" provide explicit type promotion and coercion
Parameters
----------
values : the ndarray that we want to maybe upcast
fill_value : what we want to fill with
dtype : if None, then use the dtype of the values, else coerce to this type
copy : if True always make a copy even if no upcast is required
"""
if is_extension_type(values):
if copy:
values = values.copy()
else:
if dtype is None:
dtype = values.dtype
new_dtype, fill_value = maybe_promote(dtype, fill_value)
if new_dtype != values.dtype:
values = values.astype(new_dtype)
elif copy:
values = values.copy()
return values, fill_value |
Change string like dtypes to object for DataFrame. select_dtypes (). | def invalidate_string_dtypes(dtype_set):
"""Change string like dtypes to object for
``DataFrame.select_dtypes()``.
"""
non_string_dtypes = dtype_set - {np.dtype('S').type, np.dtype('<U').type}
if non_string_dtypes != dtype_set:
raise TypeError("string dtypes are not allowed, use 'object' instead") |
coerce the indexer input array to the smallest dtype possible | def coerce_indexer_dtype(indexer, categories):
""" coerce the indexer input array to the smallest dtype possible """
length = len(categories)
if length < _int8_max:
return ensure_int8(indexer)
elif length < _int16_max:
return ensure_int16(indexer)
elif length < _int32_max:
return ensure_int32(indexer)
return ensure_int64(indexer) |
given a dtypes and a result set coerce the result elements to the dtypes | def coerce_to_dtypes(result, dtypes):
"""
given a dtypes and a result set, coerce the result elements to the
dtypes
"""
if len(result) != len(dtypes):
raise AssertionError("_coerce_to_dtypes requires equal len arrays")
def conv(r, dtype):
try:
if isna(r):
pass
elif dtype == _NS_DTYPE:
r = tslibs.Timestamp(r)
elif dtype == _TD_DTYPE:
r = tslibs.Timedelta(r)
elif dtype == np.bool_:
# messy. non 0/1 integers do not get converted.
if is_integer(r) and r not in [0, 1]:
return int(r)
r = bool(r)
elif dtype.kind == 'f':
r = float(r)
elif dtype.kind == 'i':
r = int(r)
except Exception:
pass
return r
return [conv(r, dtype) for r, dtype in zip(result, dtypes)] |
Cast the elements of an array to a given dtype a nan - safe manner. | def astype_nansafe(arr, dtype, copy=True, skipna=False):
"""
Cast the elements of an array to a given dtype a nan-safe manner.
Parameters
----------
arr : ndarray
dtype : np.dtype
copy : bool, default True
If False, a view will be attempted but may fail, if
e.g. the item sizes don't align.
skipna: bool, default False
Whether or not we should skip NaN when casting as a string-type.
Raises
------
ValueError
The dtype was a datetime64/timedelta64 dtype, but it had no unit.
"""
# dispatch on extension dtype if needed
if is_extension_array_dtype(dtype):
return dtype.construct_array_type()._from_sequence(
arr, dtype=dtype, copy=copy)
if not isinstance(dtype, np.dtype):
dtype = pandas_dtype(dtype)
if issubclass(dtype.type, str):
return lib.astype_str(arr.ravel(),
skipna=skipna).reshape(arr.shape)
elif is_datetime64_dtype(arr):
if is_object_dtype(dtype):
return tslib.ints_to_pydatetime(arr.view(np.int64))
elif dtype == np.int64:
return arr.view(dtype)
# allow frequency conversions
if dtype.kind == 'M':
return arr.astype(dtype)
raise TypeError("cannot astype a datetimelike from [{from_dtype}] "
"to [{to_dtype}]".format(from_dtype=arr.dtype,
to_dtype=dtype))
elif is_timedelta64_dtype(arr):
if is_object_dtype(dtype):
return tslibs.ints_to_pytimedelta(arr.view(np.int64))
elif dtype == np.int64:
return arr.view(dtype)
if dtype not in [_INT64_DTYPE, _TD_DTYPE]:
# allow frequency conversions
# we return a float here!
if dtype.kind == 'm':
mask = isna(arr)
result = arr.astype(dtype).astype(np.float64)
result[mask] = np.nan
return result
elif dtype == _TD_DTYPE:
return arr.astype(_TD_DTYPE, copy=copy)
raise TypeError("cannot astype a timedelta from [{from_dtype}] "
"to [{to_dtype}]".format(from_dtype=arr.dtype,
to_dtype=dtype))
elif (np.issubdtype(arr.dtype, np.floating) and
np.issubdtype(dtype, np.integer)):
if not np.isfinite(arr).all():
raise ValueError('Cannot convert non-finite values (NA or inf) to '
'integer')
elif is_object_dtype(arr):
# work around NumPy brokenness, #1987
if np.issubdtype(dtype.type, np.integer):
return lib.astype_intsafe(arr.ravel(), dtype).reshape(arr.shape)
# if we have a datetime/timedelta array of objects
# then coerce to a proper dtype and recall astype_nansafe
elif is_datetime64_dtype(dtype):
from pandas import to_datetime
return astype_nansafe(to_datetime(arr).values, dtype, copy=copy)
elif is_timedelta64_dtype(dtype):
from pandas import to_timedelta
return astype_nansafe(to_timedelta(arr).values, dtype, copy=copy)
if dtype.name in ("datetime64", "timedelta64"):
msg = ("The '{dtype}' dtype has no unit. "
"Please pass in '{dtype}[ns]' instead.")
raise ValueError(msg.format(dtype=dtype.name))
if copy or is_object_dtype(arr) or is_object_dtype(dtype):
# Explicit copy, or required since NumPy can't view from / to object.
return arr.astype(dtype, copy=True)
return arr.view(dtype) |
if we have an object dtype try to coerce dates and/ or numbers | def maybe_convert_objects(values, convert_dates=True, convert_numeric=True,
convert_timedeltas=True, copy=True):
""" if we have an object dtype, try to coerce dates and/or numbers """
# if we have passed in a list or scalar
if isinstance(values, (list, tuple)):
values = np.array(values, dtype=np.object_)
if not hasattr(values, 'dtype'):
values = np.array([values], dtype=np.object_)
# convert dates
if convert_dates and values.dtype == np.object_:
# we take an aggressive stance and convert to datetime64[ns]
if convert_dates == 'coerce':
new_values = maybe_cast_to_datetime(
values, 'M8[ns]', errors='coerce')
# if we are all nans then leave me alone
if not isna(new_values).all():
values = new_values
else:
values = lib.maybe_convert_objects(values,
convert_datetime=convert_dates)
# convert timedeltas
if convert_timedeltas and values.dtype == np.object_:
if convert_timedeltas == 'coerce':
from pandas.core.tools.timedeltas import to_timedelta
new_values = to_timedelta(values, errors='coerce')
# if we are all nans then leave me alone
if not isna(new_values).all():
values = new_values
else:
values = lib.maybe_convert_objects(
values, convert_timedelta=convert_timedeltas)
# convert to numeric
if values.dtype == np.object_:
if convert_numeric:
try:
new_values = lib.maybe_convert_numeric(values, set(),
coerce_numeric=True)
# if we are all nans then leave me alone
if not isna(new_values).all():
values = new_values
except Exception:
pass
else:
# soft-conversion
values = lib.maybe_convert_objects(values)
values = values.copy() if copy else values
return values |
if we have an object dtype try to coerce dates and/ or numbers | def soft_convert_objects(values, datetime=True, numeric=True, timedelta=True,
coerce=False, copy=True):
""" if we have an object dtype, try to coerce dates and/or numbers """
conversion_count = sum((datetime, numeric, timedelta))
if conversion_count == 0:
raise ValueError('At least one of datetime, numeric or timedelta must '
'be True.')
elif conversion_count > 1 and coerce:
raise ValueError("Only one of 'datetime', 'numeric' or "
"'timedelta' can be True when when coerce=True.")
if isinstance(values, (list, tuple)):
# List or scalar
values = np.array(values, dtype=np.object_)
elif not hasattr(values, 'dtype'):
values = np.array([values], dtype=np.object_)
elif not is_object_dtype(values.dtype):
# If not object, do not attempt conversion
values = values.copy() if copy else values
return values
# If 1 flag is coerce, ensure 2 others are False
if coerce:
# Immediate return if coerce
if datetime:
from pandas import to_datetime
return to_datetime(values, errors='coerce').to_numpy()
elif timedelta:
from pandas import to_timedelta
return to_timedelta(values, errors='coerce').to_numpy()
elif numeric:
from pandas import to_numeric
return to_numeric(values, errors='coerce')
# Soft conversions
if datetime:
# GH 20380, when datetime is beyond year 2262, hence outside
# bound of nanosecond-resolution 64-bit integers.
try:
values = lib.maybe_convert_objects(values,
convert_datetime=datetime)
except OutOfBoundsDatetime:
pass
if timedelta and is_object_dtype(values.dtype):
# Object check to ensure only run if previous did not convert
values = lib.maybe_convert_objects(values, convert_timedelta=timedelta)
if numeric and is_object_dtype(values.dtype):
try:
converted = lib.maybe_convert_numeric(values, set(),
coerce_numeric=True)
# If all NaNs, then do not-alter
values = converted if not isna(converted).all() else values
values = values.copy() if copy else values
except Exception:
pass
return values |
we might have a array ( or single object ) that is datetime like and no dtype is passed don t change the value unless we find a datetime/ timedelta set | def maybe_infer_to_datetimelike(value, convert_dates=False):
"""
we might have a array (or single object) that is datetime like,
and no dtype is passed don't change the value unless we find a
datetime/timedelta set
this is pretty strict in that a datetime/timedelta is REQUIRED
in addition to possible nulls/string likes
Parameters
----------
value : np.array / Series / Index / list-like
convert_dates : boolean, default False
if True try really hard to convert dates (such as datetime.date), other
leave inferred dtype 'date' alone
"""
# TODO: why not timedelta?
if isinstance(value, (ABCDatetimeIndex, ABCPeriodIndex,
ABCDatetimeArray, ABCPeriodArray)):
return value
elif isinstance(value, ABCSeries):
if isinstance(value._values, ABCDatetimeIndex):
return value._values
v = value
if not is_list_like(v):
v = [v]
v = np.array(v, copy=False)
# we only care about object dtypes
if not is_object_dtype(v):
return value
shape = v.shape
if not v.ndim == 1:
v = v.ravel()
if not len(v):
return value
def try_datetime(v):
# safe coerce to datetime64
try:
# GH19671
v = tslib.array_to_datetime(v,
require_iso8601=True,
errors='raise')[0]
except ValueError:
# we might have a sequence of the same-datetimes with tz's
# if so coerce to a DatetimeIndex; if they are not the same,
# then these stay as object dtype, xref GH19671
try:
from pandas._libs.tslibs import conversion
from pandas import DatetimeIndex
values, tz = conversion.datetime_to_datetime64(v)
return DatetimeIndex(values).tz_localize(
'UTC').tz_convert(tz=tz)
except (ValueError, TypeError):
pass
except Exception:
pass
return v.reshape(shape)
def try_timedelta(v):
# safe coerce to timedelta64
# will try first with a string & object conversion
from pandas import to_timedelta
try:
return to_timedelta(v)._ndarray_values.reshape(shape)
except Exception:
return v.reshape(shape)
inferred_type = lib.infer_datetimelike_array(ensure_object(v))
if inferred_type == 'date' and convert_dates:
value = try_datetime(v)
elif inferred_type == 'datetime':
value = try_datetime(v)
elif inferred_type == 'timedelta':
value = try_timedelta(v)
elif inferred_type == 'nat':
# if all NaT, return as datetime
if isna(v).all():
value = try_datetime(v)
else:
# We have at least a NaT and a string
# try timedelta first to avoid spurious datetime conversions
# e.g. '00:00:01' is a timedelta but technically is also a datetime
value = try_timedelta(v)
if lib.infer_dtype(value, skipna=False) in ['mixed']:
# cannot skip missing values, as NaT implies that the string
# is actually a datetime
value = try_datetime(v)
return value |
try to cast the array/ value to a datetimelike dtype converting float nan to iNaT | def maybe_cast_to_datetime(value, dtype, errors='raise'):
""" try to cast the array/value to a datetimelike dtype, converting float
nan to iNaT
"""
from pandas.core.tools.timedeltas import to_timedelta
from pandas.core.tools.datetimes import to_datetime
if dtype is not None:
if isinstance(dtype, str):
dtype = np.dtype(dtype)
is_datetime64 = is_datetime64_dtype(dtype)
is_datetime64tz = is_datetime64tz_dtype(dtype)
is_timedelta64 = is_timedelta64_dtype(dtype)
if is_datetime64 or is_datetime64tz or is_timedelta64:
# Force the dtype if needed.
msg = ("The '{dtype}' dtype has no unit. "
"Please pass in '{dtype}[ns]' instead.")
if is_datetime64 and not is_dtype_equal(dtype, _NS_DTYPE):
if dtype.name in ('datetime64', 'datetime64[ns]'):
if dtype.name == 'datetime64':
raise ValueError(msg.format(dtype=dtype.name))
dtype = _NS_DTYPE
else:
raise TypeError("cannot convert datetimelike to "
"dtype [{dtype}]".format(dtype=dtype))
elif is_datetime64tz:
# our NaT doesn't support tz's
# this will coerce to DatetimeIndex with
# a matching dtype below
if is_scalar(value) and isna(value):
value = [value]
elif is_timedelta64 and not is_dtype_equal(dtype, _TD_DTYPE):
if dtype.name in ('timedelta64', 'timedelta64[ns]'):
if dtype.name == 'timedelta64':
raise ValueError(msg.format(dtype=dtype.name))
dtype = _TD_DTYPE
else:
raise TypeError("cannot convert timedeltalike to "
"dtype [{dtype}]".format(dtype=dtype))
if is_scalar(value):
if value == iNaT or isna(value):
value = iNaT
else:
value = np.array(value, copy=False)
# have a scalar array-like (e.g. NaT)
if value.ndim == 0:
value = iNaT
# we have an array of datetime or timedeltas & nulls
elif np.prod(value.shape) or not is_dtype_equal(value.dtype,
dtype):
try:
if is_datetime64:
value = to_datetime(value, errors=errors)
# GH 25843: Remove tz information since the dtype
# didn't specify one
if value.tz is not None:
value = value.tz_localize(None)
value = value._values
elif is_datetime64tz:
# The string check can be removed once issue #13712
# is solved. String data that is passed with a
# datetime64tz is assumed to be naive which should
# be localized to the timezone.
is_dt_string = is_string_dtype(value)
value = to_datetime(value, errors=errors).array
if is_dt_string:
# Strings here are naive, so directly localize
value = value.tz_localize(dtype.tz)
else:
# Numeric values are UTC at this point,
# so localize and convert
value = (value.tz_localize('UTC')
.tz_convert(dtype.tz))
elif is_timedelta64:
value = to_timedelta(value, errors=errors)._values
except (AttributeError, ValueError, TypeError):
pass
# coerce datetimelike to object
elif is_datetime64_dtype(value) and not is_datetime64_dtype(dtype):
if is_object_dtype(dtype):
if value.dtype != _NS_DTYPE:
value = value.astype(_NS_DTYPE)
ints = np.asarray(value).view('i8')
return tslib.ints_to_pydatetime(ints)
# we have a non-castable dtype that was passed
raise TypeError('Cannot cast datetime64 to {dtype}'
.format(dtype=dtype))
else:
is_array = isinstance(value, np.ndarray)
# catch a datetime/timedelta that is not of ns variety
# and no coercion specified
if is_array and value.dtype.kind in ['M', 'm']:
dtype = value.dtype
if dtype.kind == 'M' and dtype != _NS_DTYPE:
value = value.astype(_NS_DTYPE)
elif dtype.kind == 'm' and dtype != _TD_DTYPE:
value = to_timedelta(value)
# only do this if we have an array and the dtype of the array is not
# setup already we are not an integer/object, so don't bother with this
# conversion
elif not (is_array and not (issubclass(value.dtype.type, np.integer) or
value.dtype == np.object_)):
value = maybe_infer_to_datetimelike(value)
return value |
Find a common data type among the given dtypes. | def find_common_type(types):
"""
Find a common data type among the given dtypes.
Parameters
----------
types : list of dtypes
Returns
-------
pandas extension or numpy dtype
See Also
--------
numpy.find_common_type
"""
if len(types) == 0:
raise ValueError('no types given')
first = types[0]
# workaround for find_common_type([np.dtype('datetime64[ns]')] * 2)
# => object
if all(is_dtype_equal(first, t) for t in types[1:]):
return first
if any(isinstance(t, (PandasExtensionDtype, ExtensionDtype))
for t in types):
return np.object
# take lowest unit
if all(is_datetime64_dtype(t) for t in types):
return np.dtype('datetime64[ns]')
if all(is_timedelta64_dtype(t) for t in types):
return np.dtype('timedelta64[ns]')
# don't mix bool / int or float or complex
# this is different from numpy, which casts bool with float/int as int
has_bools = any(is_bool_dtype(t) for t in types)
if has_bools:
for t in types:
if is_integer_dtype(t) or is_float_dtype(t) or is_complex_dtype(t):
return np.object
return np.find_common_type(types, []) |
create np. ndarray of specified shape and dtype filled with values | def cast_scalar_to_array(shape, value, dtype=None):
"""
create np.ndarray of specified shape and dtype, filled with values
Parameters
----------
shape : tuple
value : scalar value
dtype : np.dtype, optional
dtype to coerce
Returns
-------
ndarray of shape, filled with value, of specified / inferred dtype
"""
if dtype is None:
dtype, fill_value = infer_dtype_from_scalar(value)
else:
fill_value = value
values = np.empty(shape, dtype=dtype)
values.fill(fill_value)
return values |
create a np. ndarray/ pandas type of specified shape and dtype filled with values | def construct_1d_arraylike_from_scalar(value, length, dtype):
"""
create a np.ndarray / pandas type of specified shape and dtype
filled with values
Parameters
----------
value : scalar value
length : int
dtype : pandas_dtype / np.dtype
Returns
-------
np.ndarray / pandas type of length, filled with value
"""
if is_datetime64tz_dtype(dtype):
from pandas import DatetimeIndex
subarr = DatetimeIndex([value] * length, dtype=dtype)
elif is_categorical_dtype(dtype):
from pandas import Categorical
subarr = Categorical([value] * length, dtype=dtype)
else:
if not isinstance(dtype, (np.dtype, type(np.dtype))):
dtype = dtype.dtype
if length and is_integer_dtype(dtype) and isna(value):
# coerce if we have nan for an integer dtype
dtype = np.dtype('float64')
elif isinstance(dtype, np.dtype) and dtype.kind in ("U", "S"):
# we need to coerce to object dtype to avoid
# to allow numpy to take our string as a scalar value
dtype = object
if not isna(value):
value = to_str(value)
subarr = np.empty(length, dtype=dtype)
subarr.fill(value)
return subarr |
Transform any list - like object in a 1 - dimensional numpy array of object dtype. | def construct_1d_object_array_from_listlike(values):
"""
Transform any list-like object in a 1-dimensional numpy array of object
dtype.
Parameters
----------
values : any iterable which has a len()
Raises
------
TypeError
* If `values` does not have a len()
Returns
-------
1-dimensional numpy array of dtype object
"""
# numpy will try to interpret nested lists as further dimensions, hence
# making a 1D array that contains list-likes is a bit tricky:
result = np.empty(len(values), dtype='object')
result[:] = values
return result |
Construct a new ndarray coercing values to dtype preserving NA. | def construct_1d_ndarray_preserving_na(values, dtype=None, copy=False):
"""
Construct a new ndarray, coercing `values` to `dtype`, preserving NA.
Parameters
----------
values : Sequence
dtype : numpy.dtype, optional
copy : bool, default False
Note that copies may still be made with ``copy=False`` if casting
is required.
Returns
-------
arr : ndarray[dtype]
Examples
--------
>>> np.array([1.0, 2.0, None], dtype='str')
array(['1.0', '2.0', 'None'], dtype='<U4')
>>> construct_1d_ndarray_preserving_na([1.0, 2.0, None], dtype='str')
"""
subarr = np.array(values, dtype=dtype, copy=copy)
if dtype is not None and dtype.kind in ("U", "S"):
# GH-21083
# We can't just return np.array(subarr, dtype='str') since
# NumPy will convert the non-string objects into strings
# Including NA values. Se we have to go
# string -> object -> update NA, which requires an
# additional pass over the data.
na_values = isna(values)
subarr2 = subarr.astype(object)
subarr2[na_values] = np.asarray(values, dtype=object)[na_values]
subarr = subarr2
return subarr |
Takes any dtype and returns the casted version raising for when data is incompatible with integer/ unsigned integer dtypes. | def maybe_cast_to_integer_array(arr, dtype, copy=False):
"""
Takes any dtype and returns the casted version, raising for when data is
incompatible with integer/unsigned integer dtypes.
.. versionadded:: 0.24.0
Parameters
----------
arr : array-like
The array to cast.
dtype : str, np.dtype
The integer dtype to cast the array to.
copy: boolean, default False
Whether to make a copy of the array before returning.
Returns
-------
int_arr : ndarray
An array of integer or unsigned integer dtype
Raises
------
OverflowError : the dtype is incompatible with the data
ValueError : loss of precision has occurred during casting
Examples
--------
If you try to coerce negative values to unsigned integers, it raises:
>>> Series([-1], dtype="uint64")
Traceback (most recent call last):
...
OverflowError: Trying to coerce negative values to unsigned integers
Also, if you try to coerce float values to integers, it raises:
>>> Series([1, 2, 3.5], dtype="int64")
Traceback (most recent call last):
...
ValueError: Trying to coerce float values to integers
"""
try:
if not hasattr(arr, "astype"):
casted = np.array(arr, dtype=dtype, copy=copy)
else:
casted = arr.astype(dtype, copy=copy)
except OverflowError:
raise OverflowError("The elements provided in the data cannot all be "
"casted to the dtype {dtype}".format(dtype=dtype))
if np.array_equal(arr, casted):
return casted
# We do this casting to allow for proper
# data and dtype checking.
#
# We didn't do this earlier because NumPy
# doesn't handle `uint64` correctly.
arr = np.asarray(arr)
if is_unsigned_integer_dtype(dtype) and (arr < 0).any():
raise OverflowError("Trying to coerce negative values "
"to unsigned integers")
if is_integer_dtype(dtype) and (is_float_dtype(arr) or
is_object_dtype(arr)):
raise ValueError("Trying to coerce float values to integers") |
Make a scatter plot from two DataFrame columns | def scatter_plot(data, x, y, by=None, ax=None, figsize=None, grid=False,
**kwargs):
"""
Make a scatter plot from two DataFrame columns
Parameters
----------
data : DataFrame
x : Column name for the x-axis values
y : Column name for the y-axis values
ax : Matplotlib axis object
figsize : A tuple (width, height) in inches
grid : Setting this to True will show the grid
kwargs : other plotting keyword arguments
To be passed to scatter function
Returns
-------
matplotlib.Figure
"""
import matplotlib.pyplot as plt
kwargs.setdefault('edgecolors', 'none')
def plot_group(group, ax):
xvals = group[x].values
yvals = group[y].values
ax.scatter(xvals, yvals, **kwargs)
ax.grid(grid)
if by is not None:
fig = _grouped_plot(plot_group, data, by=by, figsize=figsize, ax=ax)
else:
if ax is None:
fig = plt.figure()
ax = fig.add_subplot(111)
else:
fig = ax.get_figure()
plot_group(data, ax)
ax.set_ylabel(pprint_thing(y))
ax.set_xlabel(pprint_thing(x))
ax.grid(grid)
return fig |
Make a histogram of the DataFrame s. | def hist_frame(data, column=None, by=None, grid=True, xlabelsize=None,
xrot=None, ylabelsize=None, yrot=None, ax=None, sharex=False,
sharey=False, figsize=None, layout=None, bins=10, **kwds):
"""
Make a histogram of the DataFrame's.
A `histogram`_ is a representation of the distribution of data.
This function calls :meth:`matplotlib.pyplot.hist`, on each series in
the DataFrame, resulting in one histogram per column.
.. _histogram: https://en.wikipedia.org/wiki/Histogram
Parameters
----------
data : DataFrame
The pandas object holding the data.
column : string or sequence
If passed, will be used to limit data to a subset of columns.
by : object, optional
If passed, then used to form histograms for separate groups.
grid : bool, default True
Whether to show axis grid lines.
xlabelsize : int, default None
If specified changes the x-axis label size.
xrot : float, default None
Rotation of x axis labels. For example, a value of 90 displays the
x labels rotated 90 degrees clockwise.
ylabelsize : int, default None
If specified changes the y-axis label size.
yrot : float, default None
Rotation of y axis labels. For example, a value of 90 displays the
y labels rotated 90 degrees clockwise.
ax : Matplotlib axes object, default None
The axes to plot the histogram on.
sharex : bool, default True if ax is None else False
In case subplots=True, share x axis and set some x axis labels to
invisible; defaults to True if ax is None otherwise False if an ax
is passed in.
Note that passing in both an ax and sharex=True will alter all x axis
labels for all subplots in a figure.
sharey : bool, default False
In case subplots=True, share y axis and set some y axis labels to
invisible.
figsize : tuple
The size in inches of the figure to create. Uses the value in
`matplotlib.rcParams` by default.
layout : tuple, optional
Tuple of (rows, columns) for the layout of the histograms.
bins : integer or sequence, default 10
Number of histogram bins to be used. If an integer is given, bins + 1
bin edges are calculated and returned. If bins is a sequence, gives
bin edges, including left edge of first bin and right edge of last
bin. In this case, bins is returned unmodified.
**kwds
All other plotting keyword arguments to be passed to
:meth:`matplotlib.pyplot.hist`.
Returns
-------
matplotlib.AxesSubplot or numpy.ndarray of them
See Also
--------
matplotlib.pyplot.hist : Plot a histogram using matplotlib.
Examples
--------
.. plot::
:context: close-figs
This example draws a histogram based on the length and width of
some animals, displayed in three bins
>>> df = pd.DataFrame({
... 'length': [1.5, 0.5, 1.2, 0.9, 3],
... 'width': [0.7, 0.2, 0.15, 0.2, 1.1]
... }, index= ['pig', 'rabbit', 'duck', 'chicken', 'horse'])
>>> hist = df.hist(bins=3)
"""
_raise_if_no_mpl()
_converter._WARN = False
if by is not None:
axes = grouped_hist(data, column=column, by=by, ax=ax, grid=grid,
figsize=figsize, sharex=sharex, sharey=sharey,
layout=layout, bins=bins, xlabelsize=xlabelsize,
xrot=xrot, ylabelsize=ylabelsize,
yrot=yrot, **kwds)
return axes
if column is not None:
if not isinstance(column, (list, np.ndarray, ABCIndexClass)):
column = [column]
data = data[column]
data = data._get_numeric_data()
naxes = len(data.columns)
fig, axes = _subplots(naxes=naxes, ax=ax, squeeze=False,
sharex=sharex, sharey=sharey, figsize=figsize,
layout=layout)
_axes = _flatten(axes)
for i, col in enumerate(com.try_sort(data.columns)):
ax = _axes[i]
ax.hist(data[col].dropna().values, bins=bins, **kwds)
ax.set_title(col)
ax.grid(grid)
_set_ticks_props(axes, xlabelsize=xlabelsize, xrot=xrot,
ylabelsize=ylabelsize, yrot=yrot)
fig.subplots_adjust(wspace=0.3, hspace=0.3)
return axes |
Draw histogram of the input series using matplotlib. | def hist_series(self, by=None, ax=None, grid=True, xlabelsize=None,
xrot=None, ylabelsize=None, yrot=None, figsize=None,
bins=10, **kwds):
"""
Draw histogram of the input series using matplotlib.
Parameters
----------
by : object, optional
If passed, then used to form histograms for separate groups
ax : matplotlib axis object
If not passed, uses gca()
grid : bool, default True
Whether to show axis grid lines
xlabelsize : int, default None
If specified changes the x-axis label size
xrot : float, default None
rotation of x axis labels
ylabelsize : int, default None
If specified changes the y-axis label size
yrot : float, default None
rotation of y axis labels
figsize : tuple, default None
figure size in inches by default
bins : integer or sequence, default 10
Number of histogram bins to be used. If an integer is given, bins + 1
bin edges are calculated and returned. If bins is a sequence, gives
bin edges, including left edge of first bin and right edge of last
bin. In this case, bins is returned unmodified.
bins : integer, default 10
Number of histogram bins to be used
`**kwds` : keywords
To be passed to the actual plotting function
See Also
--------
matplotlib.axes.Axes.hist : Plot a histogram using matplotlib.
"""
import matplotlib.pyplot as plt
if by is None:
if kwds.get('layout', None) is not None:
raise ValueError("The 'layout' keyword is not supported when "
"'by' is None")
# hack until the plotting interface is a bit more unified
fig = kwds.pop('figure', plt.gcf() if plt.get_fignums() else
plt.figure(figsize=figsize))
if (figsize is not None and tuple(figsize) !=
tuple(fig.get_size_inches())):
fig.set_size_inches(*figsize, forward=True)
if ax is None:
ax = fig.gca()
elif ax.get_figure() != fig:
raise AssertionError('passed axis not bound to passed figure')
values = self.dropna().values
ax.hist(values, bins=bins, **kwds)
ax.grid(grid)
axes = np.array([ax])
_set_ticks_props(axes, xlabelsize=xlabelsize, xrot=xrot,
ylabelsize=ylabelsize, yrot=yrot)
else:
if 'figure' in kwds:
raise ValueError("Cannot pass 'figure' when using the "
"'by' argument, since a new 'Figure' instance "
"will be created")
axes = grouped_hist(self, by=by, ax=ax, grid=grid, figsize=figsize,
bins=bins, xlabelsize=xlabelsize, xrot=xrot,
ylabelsize=ylabelsize, yrot=yrot, **kwds)
if hasattr(axes, 'ndim'):
if axes.ndim == 1 and len(axes) == 1:
return axes[0]
return axes |
Grouped histogram | def grouped_hist(data, column=None, by=None, ax=None, bins=50, figsize=None,
layout=None, sharex=False, sharey=False, rot=90, grid=True,
xlabelsize=None, xrot=None, ylabelsize=None, yrot=None,
**kwargs):
"""
Grouped histogram
Parameters
----------
data : Series/DataFrame
column : object, optional
by : object, optional
ax : axes, optional
bins : int, default 50
figsize : tuple, optional
layout : optional
sharex : bool, default False
sharey : bool, default False
rot : int, default 90
grid : bool, default True
kwargs : dict, keyword arguments passed to matplotlib.Axes.hist
Returns
-------
collection of Matplotlib Axes
"""
_raise_if_no_mpl()
_converter._WARN = False
def plot_group(group, ax):
ax.hist(group.dropna().values, bins=bins, **kwargs)
xrot = xrot or rot
fig, axes = _grouped_plot(plot_group, data, column=column,
by=by, sharex=sharex, sharey=sharey, ax=ax,
figsize=figsize, layout=layout, rot=rot)
_set_ticks_props(axes, xlabelsize=xlabelsize, xrot=xrot,
ylabelsize=ylabelsize, yrot=yrot)
fig.subplots_adjust(bottom=0.15, top=0.9, left=0.1, right=0.9,
hspace=0.5, wspace=0.3)
return axes |
Make box plots from DataFrameGroupBy data. | def boxplot_frame_groupby(grouped, subplots=True, column=None, fontsize=None,
rot=0, grid=True, ax=None, figsize=None,
layout=None, sharex=False, sharey=True, **kwds):
"""
Make box plots from DataFrameGroupBy data.
Parameters
----------
grouped : Grouped DataFrame
subplots : bool
* ``False`` - no subplots will be used
* ``True`` - create a subplot for each group
column : column name or list of names, or vector
Can be any valid input to groupby
fontsize : int or string
rot : label rotation angle
grid : Setting this to True will show the grid
ax : Matplotlib axis object, default None
figsize : A tuple (width, height) in inches
layout : tuple (optional)
(rows, columns) for the layout of the plot
sharex : bool, default False
Whether x-axes will be shared among subplots
.. versionadded:: 0.23.1
sharey : bool, default True
Whether y-axes will be shared among subplots
.. versionadded:: 0.23.1
`**kwds` : Keyword Arguments
All other plotting keyword arguments to be passed to
matplotlib's boxplot function
Returns
-------
dict of key/value = group key/DataFrame.boxplot return value
or DataFrame.boxplot return value in case subplots=figures=False
Examples
--------
>>> import itertools
>>> tuples = [t for t in itertools.product(range(1000), range(4))]
>>> index = pd.MultiIndex.from_tuples(tuples, names=['lvl0', 'lvl1'])
>>> data = np.random.randn(len(index),4)
>>> df = pd.DataFrame(data, columns=list('ABCD'), index=index)
>>>
>>> grouped = df.groupby(level='lvl1')
>>> boxplot_frame_groupby(grouped)
>>>
>>> grouped = df.unstack(level='lvl1').groupby(level=0, axis=1)
>>> boxplot_frame_groupby(grouped, subplots=False)
"""
_raise_if_no_mpl()
_converter._WARN = False
if subplots is True:
naxes = len(grouped)
fig, axes = _subplots(naxes=naxes, squeeze=False,
ax=ax, sharex=sharex, sharey=sharey,
figsize=figsize, layout=layout)
axes = _flatten(axes)
from pandas.core.series import Series
ret = Series()
for (key, group), ax in zip(grouped, axes):
d = group.boxplot(ax=ax, column=column, fontsize=fontsize,
rot=rot, grid=grid, **kwds)
ax.set_title(pprint_thing(key))
ret.loc[key] = d
fig.subplots_adjust(bottom=0.15, top=0.9, left=0.1,
right=0.9, wspace=0.2)
else:
from pandas.core.reshape.concat import concat
keys, frames = zip(*grouped)
if grouped.axis == 0:
df = concat(frames, keys=keys, axis=1)
else:
if len(frames) > 1:
df = frames[0].join(frames[1::])
else:
df = frames[0]
ret = df.boxplot(column=column, fontsize=fontsize, rot=rot,
grid=grid, ax=ax, figsize=figsize,
layout=layout, **kwds)
return ret |
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