INSTRUCTION stringlengths 1 8.43k | RESPONSE stringlengths 75 104k |
|---|---|
Create an array. | def array(data: Sequence[object],
dtype: Optional[Union[str, np.dtype, ExtensionDtype]] = None,
copy: bool = True,
) -> ABCExtensionArray:
"""
Create an array.
.. versionadded:: 0.24.0
Parameters
----------
data : Sequence of objects
The scalars inside `data` should be instances of the
scalar type for `dtype`. It's expected that `data`
represents a 1-dimensional array of data.
When `data` is an Index or Series, the underlying array
will be extracted from `data`.
dtype : str, np.dtype, or ExtensionDtype, optional
The dtype to use for the array. This may be a NumPy
dtype or an extension type registered with pandas using
:meth:`pandas.api.extensions.register_extension_dtype`.
If not specified, there are two possibilities:
1. When `data` is a :class:`Series`, :class:`Index`, or
:class:`ExtensionArray`, the `dtype` will be taken
from the data.
2. Otherwise, pandas will attempt to infer the `dtype`
from the data.
Note that when `data` is a NumPy array, ``data.dtype`` is
*not* used for inferring the array type. This is because
NumPy cannot represent all the types of data that can be
held in extension arrays.
Currently, pandas will infer an extension dtype for sequences of
============================== =====================================
Scalar Type Array Type
============================== =====================================
:class:`pandas.Interval` :class:`pandas.arrays.IntervalArray`
:class:`pandas.Period` :class:`pandas.arrays.PeriodArray`
:class:`datetime.datetime` :class:`pandas.arrays.DatetimeArray`
:class:`datetime.timedelta` :class:`pandas.arrays.TimedeltaArray`
============================== =====================================
For all other cases, NumPy's usual inference rules will be used.
copy : bool, default True
Whether to copy the data, even if not necessary. Depending
on the type of `data`, creating the new array may require
copying data, even if ``copy=False``.
Returns
-------
ExtensionArray
The newly created array.
Raises
------
ValueError
When `data` is not 1-dimensional.
See Also
--------
numpy.array : Construct a NumPy array.
Series : Construct a pandas Series.
Index : Construct a pandas Index.
arrays.PandasArray : ExtensionArray wrapping a NumPy array.
Series.array : Extract the array stored within a Series.
Notes
-----
Omitting the `dtype` argument means pandas will attempt to infer the
best array type from the values in the data. As new array types are
added by pandas and 3rd party libraries, the "best" array type may
change. We recommend specifying `dtype` to ensure that
1. the correct array type for the data is returned
2. the returned array type doesn't change as new extension types
are added by pandas and third-party libraries
Additionally, if the underlying memory representation of the returned
array matters, we recommend specifying the `dtype` as a concrete object
rather than a string alias or allowing it to be inferred. For example,
a future version of pandas or a 3rd-party library may include a
dedicated ExtensionArray for string data. In this event, the following
would no longer return a :class:`arrays.PandasArray` backed by a NumPy
array.
>>> pd.array(['a', 'b'], dtype=str)
<PandasArray>
['a', 'b']
Length: 2, dtype: str32
This would instead return the new ExtensionArray dedicated for string
data. If you really need the new array to be backed by a NumPy array,
specify that in the dtype.
>>> pd.array(['a', 'b'], dtype=np.dtype("<U1"))
<PandasArray>
['a', 'b']
Length: 2, dtype: str32
Or use the dedicated constructor for the array you're expecting, and
wrap that in a PandasArray
>>> pd.array(np.array(['a', 'b'], dtype='<U1'))
<PandasArray>
['a', 'b']
Length: 2, dtype: str32
Finally, Pandas has arrays that mostly overlap with NumPy
* :class:`arrays.DatetimeArray`
* :class:`arrays.TimedeltaArray`
When data with a ``datetime64[ns]`` or ``timedelta64[ns]`` dtype is
passed, pandas will always return a ``DatetimeArray`` or ``TimedeltaArray``
rather than a ``PandasArray``. This is for symmetry with the case of
timezone-aware data, which NumPy does not natively support.
>>> pd.array(['2015', '2016'], dtype='datetime64[ns]')
<DatetimeArray>
['2015-01-01 00:00:00', '2016-01-01 00:00:00']
Length: 2, dtype: datetime64[ns]
>>> pd.array(["1H", "2H"], dtype='timedelta64[ns]')
<TimedeltaArray>
['01:00:00', '02:00:00']
Length: 2, dtype: timedelta64[ns]
Examples
--------
If a dtype is not specified, `data` is passed through to
:meth:`numpy.array`, and a :class:`arrays.PandasArray` is returned.
>>> pd.array([1, 2])
<PandasArray>
[1, 2]
Length: 2, dtype: int64
Or the NumPy dtype can be specified
>>> pd.array([1, 2], dtype=np.dtype("int32"))
<PandasArray>
[1, 2]
Length: 2, dtype: int32
You can use the string alias for `dtype`
>>> pd.array(['a', 'b', 'a'], dtype='category')
[a, b, a]
Categories (2, object): [a, b]
Or specify the actual dtype
>>> pd.array(['a', 'b', 'a'],
... dtype=pd.CategoricalDtype(['a', 'b', 'c'], ordered=True))
[a, b, a]
Categories (3, object): [a < b < c]
Because omitting the `dtype` passes the data through to NumPy,
a mixture of valid integers and NA will return a floating-point
NumPy array.
>>> pd.array([1, 2, np.nan])
<PandasArray>
[1.0, 2.0, nan]
Length: 3, dtype: float64
To use pandas' nullable :class:`pandas.arrays.IntegerArray`, specify
the dtype:
>>> pd.array([1, 2, np.nan], dtype='Int64')
<IntegerArray>
[1, 2, NaN]
Length: 3, dtype: Int64
Pandas will infer an ExtensionArray for some types of data:
>>> pd.array([pd.Period('2000', freq="D"), pd.Period("2000", freq="D")])
<PeriodArray>
['2000-01-01', '2000-01-01']
Length: 2, dtype: period[D]
`data` must be 1-dimensional. A ValueError is raised when the input
has the wrong dimensionality.
>>> pd.array(1)
Traceback (most recent call last):
...
ValueError: Cannot pass scalar '1' to 'pandas.array'.
"""
from pandas.core.arrays import (
period_array, ExtensionArray, IntervalArray, PandasArray,
DatetimeArray,
TimedeltaArray,
)
from pandas.core.internals.arrays import extract_array
if lib.is_scalar(data):
msg = (
"Cannot pass scalar '{}' to 'pandas.array'."
)
raise ValueError(msg.format(data))
data = extract_array(data, extract_numpy=True)
if dtype is None and isinstance(data, ExtensionArray):
dtype = data.dtype
# this returns None for not-found dtypes.
if isinstance(dtype, str):
dtype = registry.find(dtype) or dtype
if is_extension_array_dtype(dtype):
cls = dtype.construct_array_type()
return cls._from_sequence(data, dtype=dtype, copy=copy)
if dtype is None:
inferred_dtype = lib.infer_dtype(data, skipna=False)
if inferred_dtype == 'period':
try:
return period_array(data, copy=copy)
except tslibs.IncompatibleFrequency:
# We may have a mixture of frequencies.
# We choose to return an ndarray, rather than raising.
pass
elif inferred_dtype == 'interval':
try:
return IntervalArray(data, copy=copy)
except ValueError:
# We may have a mixture of `closed` here.
# We choose to return an ndarray, rather than raising.
pass
elif inferred_dtype.startswith('datetime'):
# datetime, datetime64
try:
return DatetimeArray._from_sequence(data, copy=copy)
except ValueError:
# Mixture of timezones, fall back to PandasArray
pass
elif inferred_dtype.startswith('timedelta'):
# timedelta, timedelta64
return TimedeltaArray._from_sequence(data, copy=copy)
# TODO(BooleanArray): handle this type
# Pandas overrides NumPy for
# 1. datetime64[ns]
# 2. timedelta64[ns]
# so that a DatetimeArray is returned.
if is_datetime64_ns_dtype(dtype):
return DatetimeArray._from_sequence(data, dtype=dtype, copy=copy)
elif is_timedelta64_ns_dtype(dtype):
return TimedeltaArray._from_sequence(data, dtype=dtype, copy=copy)
result = PandasArray._from_sequence(data, dtype=dtype, copy=copy)
return result |
Try to do platform conversion with special casing for IntervalArray. Wrapper around maybe_convert_platform that alters the default return dtype in certain cases to be compatible with IntervalArray. For example empty lists return with integer dtype instead of object dtype which is prohibited for IntervalArray. | def maybe_convert_platform_interval(values):
"""
Try to do platform conversion, with special casing for IntervalArray.
Wrapper around maybe_convert_platform that alters the default return
dtype in certain cases to be compatible with IntervalArray. For example,
empty lists return with integer dtype instead of object dtype, which is
prohibited for IntervalArray.
Parameters
----------
values : array-like
Returns
-------
array
"""
if isinstance(values, (list, tuple)) and len(values) == 0:
# GH 19016
# empty lists/tuples get object dtype by default, but this is not
# prohibited for IntervalArray, so coerce to integer instead
return np.array([], dtype=np.int64)
elif is_categorical_dtype(values):
values = np.asarray(values)
return maybe_convert_platform(values) |
Check if the object is a file - like object. | def is_file_like(obj):
"""
Check if the object is a file-like object.
For objects to be considered file-like, they must
be an iterator AND have either a `read` and/or `write`
method as an attribute.
Note: file-like objects must be iterable, but
iterable objects need not be file-like.
.. versionadded:: 0.20.0
Parameters
----------
obj : The object to check
Returns
-------
is_file_like : bool
Whether `obj` has file-like properties.
Examples
--------
>>> buffer(StringIO("data"))
>>> is_file_like(buffer)
True
>>> is_file_like([1, 2, 3])
False
"""
if not (hasattr(obj, 'read') or hasattr(obj, 'write')):
return False
if not hasattr(obj, "__iter__"):
return False
return True |
Check if the object is list - like. | def is_list_like(obj, allow_sets=True):
"""
Check if the object is list-like.
Objects that are considered list-like are for example Python
lists, tuples, sets, NumPy arrays, and Pandas Series.
Strings and datetime objects, however, are not considered list-like.
Parameters
----------
obj : The object to check
allow_sets : boolean, default True
If this parameter is False, sets will not be considered list-like
.. versionadded:: 0.24.0
Returns
-------
is_list_like : bool
Whether `obj` has list-like properties.
Examples
--------
>>> is_list_like([1, 2, 3])
True
>>> is_list_like({1, 2, 3})
True
>>> is_list_like(datetime(2017, 1, 1))
False
>>> is_list_like("foo")
False
>>> is_list_like(1)
False
>>> is_list_like(np.array([2]))
True
>>> is_list_like(np.array(2)))
False
"""
return (isinstance(obj, abc.Iterable) and
# we do not count strings/unicode/bytes as list-like
not isinstance(obj, (str, bytes)) and
# exclude zero-dimensional numpy arrays, effectively scalars
not (isinstance(obj, np.ndarray) and obj.ndim == 0) and
# exclude sets if allow_sets is False
not (allow_sets is False and isinstance(obj, abc.Set))) |
Check if the object is list - like and that all of its elements are also list - like. | def is_nested_list_like(obj):
"""
Check if the object is list-like, and that all of its elements
are also list-like.
.. versionadded:: 0.20.0
Parameters
----------
obj : The object to check
Returns
-------
is_list_like : bool
Whether `obj` has list-like properties.
Examples
--------
>>> is_nested_list_like([[1, 2, 3]])
True
>>> is_nested_list_like([{1, 2, 3}, {1, 2, 3}])
True
>>> is_nested_list_like(["foo"])
False
>>> is_nested_list_like([])
False
>>> is_nested_list_like([[1, 2, 3], 1])
False
Notes
-----
This won't reliably detect whether a consumable iterator (e. g.
a generator) is a nested-list-like without consuming the iterator.
To avoid consuming it, we always return False if the outer container
doesn't define `__len__`.
See Also
--------
is_list_like
"""
return (is_list_like(obj) and hasattr(obj, '__len__') and
len(obj) > 0 and all(is_list_like(item) for item in obj)) |
Check if the object is dict - like. | def is_dict_like(obj):
"""
Check if the object is dict-like.
Parameters
----------
obj : The object to check
Returns
-------
is_dict_like : bool
Whether `obj` has dict-like properties.
Examples
--------
>>> is_dict_like({1: 2})
True
>>> is_dict_like([1, 2, 3])
False
>>> is_dict_like(dict)
False
>>> is_dict_like(dict())
True
"""
dict_like_attrs = ("__getitem__", "keys", "__contains__")
return (all(hasattr(obj, attr) for attr in dict_like_attrs)
# [GH 25196] exclude classes
and not isinstance(obj, type)) |
Check if the object is a sequence of objects. String types are not included as sequences here. | def is_sequence(obj):
"""
Check if the object is a sequence of objects.
String types are not included as sequences here.
Parameters
----------
obj : The object to check
Returns
-------
is_sequence : bool
Whether `obj` is a sequence of objects.
Examples
--------
>>> l = [1, 2, 3]
>>>
>>> is_sequence(l)
True
>>> is_sequence(iter(l))
False
"""
try:
iter(obj) # Can iterate over it.
len(obj) # Has a length associated with it.
return not isinstance(obj, (str, bytes))
except (TypeError, AttributeError):
return False |
This is called upon unpickling rather than the default which doesn t have arguments and breaks __new__ | def _new_DatetimeIndex(cls, d):
""" This is called upon unpickling, rather than the default which doesn't
have arguments and breaks __new__ """
if "data" in d and not isinstance(d["data"], DatetimeIndex):
# Avoid need to verify integrity by calling simple_new directly
data = d.pop("data")
result = cls._simple_new(data, **d)
else:
with warnings.catch_warnings():
# we ignore warnings from passing verify_integrity=False
# TODO: If we knew what was going in to **d, we might be able to
# go through _simple_new instead
warnings.simplefilter("ignore")
result = cls.__new__(cls, verify_integrity=False, **d)
return result |
Return a fixed frequency DatetimeIndex. | def date_range(start=None, end=None, periods=None, freq=None, tz=None,
normalize=False, name=None, closed=None, **kwargs):
"""
Return a fixed frequency DatetimeIndex.
Parameters
----------
start : str or datetime-like, optional
Left bound for generating dates.
end : str or datetime-like, optional
Right bound for generating dates.
periods : integer, optional
Number of periods to generate.
freq : str or DateOffset, default 'D'
Frequency strings can have multiples, e.g. '5H'. See
:ref:`here <timeseries.offset_aliases>` for a list of
frequency aliases.
tz : str or tzinfo, optional
Time zone name for returning localized DatetimeIndex, for example
'Asia/Hong_Kong'. By default, the resulting DatetimeIndex is
timezone-naive.
normalize : bool, default False
Normalize start/end dates to midnight before generating date range.
name : str, default None
Name of the resulting DatetimeIndex.
closed : {None, 'left', 'right'}, optional
Make the interval closed with respect to the given frequency to
the 'left', 'right', or both sides (None, the default).
**kwargs
For compatibility. Has no effect on the result.
Returns
-------
rng : DatetimeIndex
See Also
--------
DatetimeIndex : An immutable container for datetimes.
timedelta_range : Return a fixed frequency TimedeltaIndex.
period_range : Return a fixed frequency PeriodIndex.
interval_range : Return a fixed frequency IntervalIndex.
Notes
-----
Of the four parameters ``start``, ``end``, ``periods``, and ``freq``,
exactly three must be specified. If ``freq`` is omitted, the resulting
``DatetimeIndex`` will have ``periods`` linearly spaced elements between
``start`` and ``end`` (closed on both sides).
To learn more about the frequency strings, please see `this link
<http://pandas.pydata.org/pandas-docs/stable/timeseries.html#offset-aliases>`__.
Examples
--------
**Specifying the values**
The next four examples generate the same `DatetimeIndex`, but vary
the combination of `start`, `end` and `periods`.
Specify `start` and `end`, with the default daily frequency.
>>> pd.date_range(start='1/1/2018', end='1/08/2018')
DatetimeIndex(['2018-01-01', '2018-01-02', '2018-01-03', '2018-01-04',
'2018-01-05', '2018-01-06', '2018-01-07', '2018-01-08'],
dtype='datetime64[ns]', freq='D')
Specify `start` and `periods`, the number of periods (days).
>>> pd.date_range(start='1/1/2018', periods=8)
DatetimeIndex(['2018-01-01', '2018-01-02', '2018-01-03', '2018-01-04',
'2018-01-05', '2018-01-06', '2018-01-07', '2018-01-08'],
dtype='datetime64[ns]', freq='D')
Specify `end` and `periods`, the number of periods (days).
>>> pd.date_range(end='1/1/2018', periods=8)
DatetimeIndex(['2017-12-25', '2017-12-26', '2017-12-27', '2017-12-28',
'2017-12-29', '2017-12-30', '2017-12-31', '2018-01-01'],
dtype='datetime64[ns]', freq='D')
Specify `start`, `end`, and `periods`; the frequency is generated
automatically (linearly spaced).
>>> pd.date_range(start='2018-04-24', end='2018-04-27', periods=3)
DatetimeIndex(['2018-04-24 00:00:00', '2018-04-25 12:00:00',
'2018-04-27 00:00:00'],
dtype='datetime64[ns]', freq=None)
**Other Parameters**
Changed the `freq` (frequency) to ``'M'`` (month end frequency).
>>> pd.date_range(start='1/1/2018', periods=5, freq='M')
DatetimeIndex(['2018-01-31', '2018-02-28', '2018-03-31', '2018-04-30',
'2018-05-31'],
dtype='datetime64[ns]', freq='M')
Multiples are allowed
>>> pd.date_range(start='1/1/2018', periods=5, freq='3M')
DatetimeIndex(['2018-01-31', '2018-04-30', '2018-07-31', '2018-10-31',
'2019-01-31'],
dtype='datetime64[ns]', freq='3M')
`freq` can also be specified as an Offset object.
>>> pd.date_range(start='1/1/2018', periods=5, freq=pd.offsets.MonthEnd(3))
DatetimeIndex(['2018-01-31', '2018-04-30', '2018-07-31', '2018-10-31',
'2019-01-31'],
dtype='datetime64[ns]', freq='3M')
Specify `tz` to set the timezone.
>>> pd.date_range(start='1/1/2018', periods=5, tz='Asia/Tokyo')
DatetimeIndex(['2018-01-01 00:00:00+09:00', '2018-01-02 00:00:00+09:00',
'2018-01-03 00:00:00+09:00', '2018-01-04 00:00:00+09:00',
'2018-01-05 00:00:00+09:00'],
dtype='datetime64[ns, Asia/Tokyo]', freq='D')
`closed` controls whether to include `start` and `end` that are on the
boundary. The default includes boundary points on either end.
>>> pd.date_range(start='2017-01-01', end='2017-01-04', closed=None)
DatetimeIndex(['2017-01-01', '2017-01-02', '2017-01-03', '2017-01-04'],
dtype='datetime64[ns]', freq='D')
Use ``closed='left'`` to exclude `end` if it falls on the boundary.
>>> pd.date_range(start='2017-01-01', end='2017-01-04', closed='left')
DatetimeIndex(['2017-01-01', '2017-01-02', '2017-01-03'],
dtype='datetime64[ns]', freq='D')
Use ``closed='right'`` to exclude `start` if it falls on the boundary.
>>> pd.date_range(start='2017-01-01', end='2017-01-04', closed='right')
DatetimeIndex(['2017-01-02', '2017-01-03', '2017-01-04'],
dtype='datetime64[ns]', freq='D')
"""
if freq is None and com._any_none(periods, start, end):
freq = 'D'
dtarr = DatetimeArray._generate_range(
start=start, end=end, periods=periods,
freq=freq, tz=tz, normalize=normalize,
closed=closed, **kwargs)
return DatetimeIndex._simple_new(
dtarr, tz=dtarr.tz, freq=dtarr.freq, name=name) |
Return a fixed frequency DatetimeIndex with business day as the default frequency | def bdate_range(start=None, end=None, periods=None, freq='B', tz=None,
normalize=True, name=None, weekmask=None, holidays=None,
closed=None, **kwargs):
"""
Return a fixed frequency DatetimeIndex, with business day as the default
frequency
Parameters
----------
start : string or datetime-like, default None
Left bound for generating dates.
end : string or datetime-like, default None
Right bound for generating dates.
periods : integer, default None
Number of periods to generate.
freq : string or DateOffset, default 'B' (business daily)
Frequency strings can have multiples, e.g. '5H'.
tz : string or None
Time zone name for returning localized DatetimeIndex, for example
Asia/Beijing.
normalize : bool, default False
Normalize start/end dates to midnight before generating date range.
name : string, default None
Name of the resulting DatetimeIndex.
weekmask : string or None, default None
Weekmask of valid business days, passed to ``numpy.busdaycalendar``,
only used when custom frequency strings are passed. The default
value None is equivalent to 'Mon Tue Wed Thu Fri'.
.. versionadded:: 0.21.0
holidays : list-like or None, default None
Dates to exclude from the set of valid business days, passed to
``numpy.busdaycalendar``, only used when custom frequency strings
are passed.
.. versionadded:: 0.21.0
closed : string, default None
Make the interval closed with respect to the given frequency to
the 'left', 'right', or both sides (None).
**kwargs
For compatibility. Has no effect on the result.
Returns
-------
DatetimeIndex
Notes
-----
Of the four parameters: ``start``, ``end``, ``periods``, and ``freq``,
exactly three must be specified. Specifying ``freq`` is a requirement
for ``bdate_range``. Use ``date_range`` if specifying ``freq`` is not
desired.
To learn more about the frequency strings, please see `this link
<http://pandas.pydata.org/pandas-docs/stable/timeseries.html#offset-aliases>`__.
Examples
--------
Note how the two weekend days are skipped in the result.
>>> pd.bdate_range(start='1/1/2018', end='1/08/2018')
DatetimeIndex(['2018-01-01', '2018-01-02', '2018-01-03', '2018-01-04',
'2018-01-05', '2018-01-08'],
dtype='datetime64[ns]', freq='B')
"""
if freq is None:
msg = 'freq must be specified for bdate_range; use date_range instead'
raise TypeError(msg)
if is_string_like(freq) and freq.startswith('C'):
try:
weekmask = weekmask or 'Mon Tue Wed Thu Fri'
freq = prefix_mapping[freq](holidays=holidays, weekmask=weekmask)
except (KeyError, TypeError):
msg = 'invalid custom frequency string: {freq}'.format(freq=freq)
raise ValueError(msg)
elif holidays or weekmask:
msg = ('a custom frequency string is required when holidays or '
'weekmask are passed, got frequency {freq}').format(freq=freq)
raise ValueError(msg)
return date_range(start=start, end=end, periods=periods,
freq=freq, tz=tz, normalize=normalize, name=name,
closed=closed, **kwargs) |
Return a fixed frequency DatetimeIndex with CustomBusinessDay as the default frequency | def cdate_range(start=None, end=None, periods=None, freq='C', tz=None,
normalize=True, name=None, closed=None, **kwargs):
"""
Return a fixed frequency DatetimeIndex, with CustomBusinessDay as the
default frequency
.. deprecated:: 0.21.0
Parameters
----------
start : string or datetime-like, default None
Left bound for generating dates
end : string or datetime-like, default None
Right bound for generating dates
periods : integer, default None
Number of periods to generate
freq : string or DateOffset, default 'C' (CustomBusinessDay)
Frequency strings can have multiples, e.g. '5H'
tz : string, default None
Time zone name for returning localized DatetimeIndex, for example
Asia/Beijing
normalize : bool, default False
Normalize start/end dates to midnight before generating date range
name : string, default None
Name of the resulting DatetimeIndex
weekmask : string, Default 'Mon Tue Wed Thu Fri'
weekmask of valid business days, passed to ``numpy.busdaycalendar``
holidays : list
list/array of dates to exclude from the set of valid business days,
passed to ``numpy.busdaycalendar``
closed : string, default None
Make the interval closed with respect to the given frequency to
the 'left', 'right', or both sides (None)
Notes
-----
Of the three parameters: ``start``, ``end``, and ``periods``, exactly two
must be specified.
To learn more about the frequency strings, please see `this link
<http://pandas.pydata.org/pandas-docs/stable/timeseries.html#offset-aliases>`__.
Returns
-------
rng : DatetimeIndex
"""
warnings.warn("cdate_range is deprecated and will be removed in a future "
"version, instead use pd.bdate_range(..., freq='{freq}')"
.format(freq=freq), FutureWarning, stacklevel=2)
if freq == 'C':
holidays = kwargs.pop('holidays', [])
weekmask = kwargs.pop('weekmask', 'Mon Tue Wed Thu Fri')
freq = CDay(holidays=holidays, weekmask=weekmask)
return date_range(start=start, end=end, periods=periods, freq=freq,
tz=tz, normalize=normalize, name=name,
closed=closed, **kwargs) |
Split data into blocks & return conformed data. | def _create_blocks(self):
"""
Split data into blocks & return conformed data.
"""
obj, index = self._convert_freq()
if index is not None:
index = self._on
# filter out the on from the object
if self.on is not None:
if obj.ndim == 2:
obj = obj.reindex(columns=obj.columns.difference([self.on]),
copy=False)
blocks = obj._to_dict_of_blocks(copy=False).values()
return blocks, obj, index |
Sub - classes to define. Return a sliced object. | def _gotitem(self, key, ndim, subset=None):
"""
Sub-classes to define. Return a sliced object.
Parameters
----------
key : str / list of selections
ndim : 1,2
requested ndim of result
subset : object, default None
subset to act on
"""
# create a new object to prevent aliasing
if subset is None:
subset = self.obj
self = self._shallow_copy(subset)
self._reset_cache()
if subset.ndim == 2:
if is_scalar(key) and key in subset or is_list_like(key):
self._selection = key
return self |
Return index as ndarrays. | def _get_index(self, index=None):
"""
Return index as ndarrays.
Returns
-------
tuple of (index, index_as_ndarray)
"""
if self.is_freq_type:
if index is None:
index = self._on
return index, index.asi8
return index, index |
Wrap a single result. | def _wrap_result(self, result, block=None, obj=None):
"""
Wrap a single result.
"""
if obj is None:
obj = self._selected_obj
index = obj.index
if isinstance(result, np.ndarray):
# coerce if necessary
if block is not None:
if is_timedelta64_dtype(block.values.dtype):
from pandas import to_timedelta
result = to_timedelta(
result.ravel(), unit='ns').values.reshape(result.shape)
if result.ndim == 1:
from pandas import Series
return Series(result, index, name=obj.name)
return type(obj)(result, index=index, columns=block.columns)
return result |
Wrap the results. | def _wrap_results(self, results, blocks, obj):
"""
Wrap the results.
Parameters
----------
results : list of ndarrays
blocks : list of blocks
obj : conformed data (may be resampled)
"""
from pandas import Series, concat
from pandas.core.index import ensure_index
final = []
for result, block in zip(results, blocks):
result = self._wrap_result(result, block=block, obj=obj)
if result.ndim == 1:
return result
final.append(result)
# if we have an 'on' column
# we want to put it back into the results
# in the same location
columns = self._selected_obj.columns
if self.on is not None and not self._on.equals(obj.index):
name = self._on.name
final.append(Series(self._on, index=obj.index, name=name))
if self._selection is not None:
selection = ensure_index(self._selection)
# need to reorder to include original location of
# the on column (if its not already there)
if name not in selection:
columns = self.obj.columns
indexer = columns.get_indexer(selection.tolist() + [name])
columns = columns.take(sorted(indexer))
if not len(final):
return obj.astype('float64')
return concat(final, axis=1).reindex(columns=columns, copy=False) |
Center the result in the window. | def _center_window(self, result, window):
"""
Center the result in the window.
"""
if self.axis > result.ndim - 1:
raise ValueError("Requested axis is larger then no. of argument "
"dimensions")
offset = _offset(window, True)
if offset > 0:
if isinstance(result, (ABCSeries, ABCDataFrame)):
result = result.slice_shift(-offset, axis=self.axis)
else:
lead_indexer = [slice(None)] * result.ndim
lead_indexer[self.axis] = slice(offset, None)
result = np.copy(result[tuple(lead_indexer)])
return result |
Provide validation for our window type return the window we have already been validated. | def _prep_window(self, **kwargs):
"""
Provide validation for our window type, return the window
we have already been validated.
"""
window = self._get_window()
if isinstance(window, (list, tuple, np.ndarray)):
return com.asarray_tuplesafe(window).astype(float)
elif is_integer(window):
import scipy.signal as sig
# the below may pop from kwargs
def _validate_win_type(win_type, kwargs):
arg_map = {'kaiser': ['beta'],
'gaussian': ['std'],
'general_gaussian': ['power', 'width'],
'slepian': ['width']}
if win_type in arg_map:
return tuple([win_type] + _pop_args(win_type,
arg_map[win_type],
kwargs))
return win_type
def _pop_args(win_type, arg_names, kwargs):
msg = '%s window requires %%s' % win_type
all_args = []
for n in arg_names:
if n not in kwargs:
raise ValueError(msg % n)
all_args.append(kwargs.pop(n))
return all_args
win_type = _validate_win_type(self.win_type, kwargs)
# GH #15662. `False` makes symmetric window, rather than periodic.
return sig.get_window(win_type, window, False).astype(float) |
Applies a moving window of type window_type on the data. | def _apply_window(self, mean=True, **kwargs):
"""
Applies a moving window of type ``window_type`` on the data.
Parameters
----------
mean : bool, default True
If True computes weighted mean, else weighted sum
Returns
-------
y : same type as input argument
"""
window = self._prep_window(**kwargs)
center = self.center
blocks, obj, index = self._create_blocks()
results = []
for b in blocks:
try:
values = self._prep_values(b.values)
except TypeError:
results.append(b.values.copy())
continue
if values.size == 0:
results.append(values.copy())
continue
offset = _offset(window, center)
additional_nans = np.array([np.NaN] * offset)
def f(arg, *args, **kwargs):
minp = _use_window(self.min_periods, len(window))
return libwindow.roll_window(np.concatenate((arg,
additional_nans))
if center else arg, window, minp,
avg=mean)
result = np.apply_along_axis(f, self.axis, values)
if center:
result = self._center_window(result, window)
results.append(result)
return self._wrap_results(results, blocks, obj) |
Dispatch to apply ; we are stripping all of the _apply kwargs and performing the original function call on the grouped object. | def _apply(self, func, name, window=None, center=None,
check_minp=None, **kwargs):
"""
Dispatch to apply; we are stripping all of the _apply kwargs and
performing the original function call on the grouped object.
"""
def f(x, name=name, *args):
x = self._shallow_copy(x)
if isinstance(name, str):
return getattr(x, name)(*args, **kwargs)
return x.apply(name, *args, **kwargs)
return self._groupby.apply(f) |
Rolling statistical measure using supplied function. | def _apply(self, func, name=None, window=None, center=None,
check_minp=None, **kwargs):
"""
Rolling statistical measure using supplied function.
Designed to be used with passed-in Cython array-based functions.
Parameters
----------
func : str/callable to apply
name : str, optional
name of this function
window : int/array, default to _get_window()
center : bool, default to self.center
check_minp : function, default to _use_window
Returns
-------
y : type of input
"""
if center is None:
center = self.center
if window is None:
window = self._get_window()
if check_minp is None:
check_minp = _use_window
blocks, obj, index = self._create_blocks()
index, indexi = self._get_index(index=index)
results = []
for b in blocks:
values = self._prep_values(b.values)
if values.size == 0:
results.append(values.copy())
continue
# if we have a string function name, wrap it
if isinstance(func, str):
cfunc = getattr(libwindow, func, None)
if cfunc is None:
raise ValueError("we do not support this function "
"in libwindow.{func}".format(func=func))
def func(arg, window, min_periods=None, closed=None):
minp = check_minp(min_periods, window)
# ensure we are only rolling on floats
arg = ensure_float64(arg)
return cfunc(arg,
window, minp, indexi, closed, **kwargs)
# calculation function
if center:
offset = _offset(window, center)
additional_nans = np.array([np.NaN] * offset)
def calc(x):
return func(np.concatenate((x, additional_nans)),
window, min_periods=self.min_periods,
closed=self.closed)
else:
def calc(x):
return func(x, window, min_periods=self.min_periods,
closed=self.closed)
with np.errstate(all='ignore'):
if values.ndim > 1:
result = np.apply_along_axis(calc, self.axis, values)
else:
result = calc(values)
if center:
result = self._center_window(result, window)
results.append(result)
return self._wrap_results(results, blocks, obj) |
Validate on is_monotonic. | def _validate_monotonic(self):
"""
Validate on is_monotonic.
"""
if not self._on.is_monotonic:
formatted = self.on or 'index'
raise ValueError("{0} must be "
"monotonic".format(formatted)) |
Validate & return window frequency. | def _validate_freq(self):
"""
Validate & return window frequency.
"""
from pandas.tseries.frequencies import to_offset
try:
return to_offset(self.window)
except (TypeError, ValueError):
raise ValueError("passed window {0} is not "
"compatible with a datetimelike "
"index".format(self.window)) |
Get the window length over which to perform some operation. | def _get_window(self, other=None):
"""
Get the window length over which to perform some operation.
Parameters
----------
other : object, default None
The other object that is involved in the operation.
Such an object is involved for operations like covariance.
Returns
-------
window : int
The window length.
"""
axis = self.obj._get_axis(self.axis)
length = len(axis) + (other is not None) * len(axis)
other = self.min_periods or -1
return max(length, other) |
Rolling statistical measure using supplied function. Designed to be used with passed - in Cython array - based functions. | def _apply(self, func, **kwargs):
"""
Rolling statistical measure using supplied function. Designed to be
used with passed-in Cython array-based functions.
Parameters
----------
func : str/callable to apply
Returns
-------
y : same type as input argument
"""
blocks, obj, index = self._create_blocks()
results = []
for b in blocks:
try:
values = self._prep_values(b.values)
except TypeError:
results.append(b.values.copy())
continue
if values.size == 0:
results.append(values.copy())
continue
# if we have a string function name, wrap it
if isinstance(func, str):
cfunc = getattr(libwindow, func, None)
if cfunc is None:
raise ValueError("we do not support this function "
"in libwindow.{func}".format(func=func))
def func(arg):
return cfunc(arg, self.com, int(self.adjust),
int(self.ignore_na), int(self.min_periods))
results.append(np.apply_along_axis(func, self.axis, values))
return self._wrap_results(results, blocks, obj) |
Exponential weighted moving average. | def mean(self, *args, **kwargs):
"""
Exponential weighted moving average.
Parameters
----------
*args, **kwargs
Arguments and keyword arguments to be passed into func.
"""
nv.validate_window_func('mean', args, kwargs)
return self._apply('ewma', **kwargs) |
Exponential weighted moving stddev. | def std(self, bias=False, *args, **kwargs):
"""
Exponential weighted moving stddev.
"""
nv.validate_window_func('std', args, kwargs)
return _zsqrt(self.var(bias=bias, **kwargs)) |
Exponential weighted moving variance. | def var(self, bias=False, *args, **kwargs):
"""
Exponential weighted moving variance.
"""
nv.validate_window_func('var', args, kwargs)
def f(arg):
return libwindow.ewmcov(arg, arg, self.com, int(self.adjust),
int(self.ignore_na), int(self.min_periods),
int(bias))
return self._apply(f, **kwargs) |
Exponential weighted sample covariance. | def cov(self, other=None, pairwise=None, bias=False, **kwargs):
"""
Exponential weighted sample covariance.
"""
if other is None:
other = self._selected_obj
# only default unset
pairwise = True if pairwise is None else pairwise
other = self._shallow_copy(other)
def _get_cov(X, Y):
X = self._shallow_copy(X)
Y = self._shallow_copy(Y)
cov = libwindow.ewmcov(X._prep_values(), Y._prep_values(),
self.com, int(self.adjust),
int(self.ignore_na), int(self.min_periods),
int(bias))
return X._wrap_result(cov)
return _flex_binary_moment(self._selected_obj, other._selected_obj,
_get_cov, pairwise=bool(pairwise)) |
Exponential weighted sample correlation. | def corr(self, other=None, pairwise=None, **kwargs):
"""
Exponential weighted sample correlation.
"""
if other is None:
other = self._selected_obj
# only default unset
pairwise = True if pairwise is None else pairwise
other = self._shallow_copy(other)
def _get_corr(X, Y):
X = self._shallow_copy(X)
Y = self._shallow_copy(Y)
def _cov(x, y):
return libwindow.ewmcov(x, y, self.com, int(self.adjust),
int(self.ignore_na),
int(self.min_periods),
1)
x_values = X._prep_values()
y_values = Y._prep_values()
with np.errstate(all='ignore'):
cov = _cov(x_values, y_values)
x_var = _cov(x_values, x_values)
y_var = _cov(y_values, y_values)
corr = cov / _zsqrt(x_var * y_var)
return X._wrap_result(corr)
return _flex_binary_moment(self._selected_obj, other._selected_obj,
_get_corr, pairwise=bool(pairwise)) |
Makes sure that time and panels are conformable. | def _ensure_like_indices(time, panels):
"""
Makes sure that time and panels are conformable.
"""
n_time = len(time)
n_panel = len(panels)
u_panels = np.unique(panels) # this sorts!
u_time = np.unique(time)
if len(u_time) == n_time:
time = np.tile(u_time, len(u_panels))
if len(u_panels) == n_panel:
panels = np.repeat(u_panels, len(u_time))
return time, panels |
Returns a multi - index suitable for a panel - like DataFrame. | def panel_index(time, panels, names=None):
"""
Returns a multi-index suitable for a panel-like DataFrame.
Parameters
----------
time : array-like
Time index, does not have to repeat
panels : array-like
Panel index, does not have to repeat
names : list, optional
List containing the names of the indices
Returns
-------
multi_index : MultiIndex
Time index is the first level, the panels are the second level.
Examples
--------
>>> years = range(1960,1963)
>>> panels = ['A', 'B', 'C']
>>> panel_idx = panel_index(years, panels)
>>> panel_idx
MultiIndex([(1960, 'A'), (1961, 'A'), (1962, 'A'), (1960, 'B'),
(1961, 'B'), (1962, 'B'), (1960, 'C'), (1961, 'C'),
(1962, 'C')], dtype=object)
or
>>> years = np.repeat(range(1960,1963), 3)
>>> panels = np.tile(['A', 'B', 'C'], 3)
>>> panel_idx = panel_index(years, panels)
>>> panel_idx
MultiIndex([(1960, 'A'), (1960, 'B'), (1960, 'C'), (1961, 'A'),
(1961, 'B'), (1961, 'C'), (1962, 'A'), (1962, 'B'),
(1962, 'C')], dtype=object)
"""
if names is None:
names = ['time', 'panel']
time, panels = _ensure_like_indices(time, panels)
return MultiIndex.from_arrays([time, panels], sortorder=None, names=names) |
Generate ND initialization ; axes are passed as required objects to __init__. | def _init_data(self, data, copy, dtype, **kwargs):
"""
Generate ND initialization; axes are passed
as required objects to __init__.
"""
if data is None:
data = {}
if dtype is not None:
dtype = self._validate_dtype(dtype)
passed_axes = [kwargs.pop(a, None) for a in self._AXIS_ORDERS]
if kwargs:
raise TypeError('_init_data() got an unexpected keyword '
'argument "{0}"'.format(list(kwargs.keys())[0]))
axes = None
if isinstance(data, BlockManager):
if com._any_not_none(*passed_axes):
axes = [x if x is not None else y
for x, y in zip(passed_axes, data.axes)]
mgr = data
elif isinstance(data, dict):
mgr = self._init_dict(data, passed_axes, dtype=dtype)
copy = False
dtype = None
elif isinstance(data, (np.ndarray, list)):
mgr = self._init_matrix(data, passed_axes, dtype=dtype, copy=copy)
copy = False
dtype = None
elif is_scalar(data) and com._all_not_none(*passed_axes):
values = cast_scalar_to_array([len(x) for x in passed_axes],
data, dtype=dtype)
mgr = self._init_matrix(values, passed_axes, dtype=values.dtype,
copy=False)
copy = False
else: # pragma: no cover
raise ValueError('Panel constructor not properly called!')
NDFrame.__init__(self, mgr, axes=axes, copy=copy, dtype=dtype) |
Construct Panel from dict of DataFrame objects. | def from_dict(cls, data, intersect=False, orient='items', dtype=None):
"""
Construct Panel from dict of DataFrame objects.
Parameters
----------
data : dict
{field : DataFrame}
intersect : boolean
Intersect indexes of input DataFrames
orient : {'items', 'minor'}, default 'items'
The "orientation" of the data. If the keys of the passed dict
should be the items of the result panel, pass 'items'
(default). Otherwise if the columns of the values of the passed
DataFrame objects should be the items (which in the case of
mixed-dtype data you should do), instead pass 'minor'
dtype : dtype, default None
Data type to force, otherwise infer
Returns
-------
Panel
"""
from collections import defaultdict
orient = orient.lower()
if orient == 'minor':
new_data = defaultdict(OrderedDict)
for col, df in data.items():
for item, s in df.items():
new_data[item][col] = s
data = new_data
elif orient != 'items': # pragma: no cover
raise ValueError('Orientation must be one of {items, minor}.')
d = cls._homogenize_dict(cls, data, intersect=intersect, dtype=dtype)
ks = list(d['data'].keys())
if not isinstance(d['data'], OrderedDict):
ks = list(sorted(ks))
d[cls._info_axis_name] = Index(ks)
return cls(**d) |
Get my plane axes indexes: these are already ( as compared with higher level planes ) as we are returning a DataFrame axes indexes. | def _get_plane_axes_index(self, axis):
"""
Get my plane axes indexes: these are already
(as compared with higher level planes),
as we are returning a DataFrame axes indexes.
"""
axis_name = self._get_axis_name(axis)
if axis_name == 'major_axis':
index = 'minor_axis'
columns = 'items'
if axis_name == 'minor_axis':
index = 'major_axis'
columns = 'items'
elif axis_name == 'items':
index = 'major_axis'
columns = 'minor_axis'
return index, columns |
Get my plane axes indexes: these are already ( as compared with higher level planes ) as we are returning a DataFrame axes. | def _get_plane_axes(self, axis):
"""
Get my plane axes indexes: these are already
(as compared with higher level planes),
as we are returning a DataFrame axes.
"""
return [self._get_axis(axi)
for axi in self._get_plane_axes_index(axis)] |
Write each DataFrame in Panel to a separate excel sheet. | def to_excel(self, path, na_rep='', engine=None, **kwargs):
"""
Write each DataFrame in Panel to a separate excel sheet.
Parameters
----------
path : string or ExcelWriter object
File path or existing ExcelWriter
na_rep : string, default ''
Missing data representation
engine : string, default None
write engine to use - you can also set this via the options
``io.excel.xlsx.writer``, ``io.excel.xls.writer``, and
``io.excel.xlsm.writer``.
Other Parameters
----------------
float_format : string, default None
Format string for floating point numbers
cols : sequence, optional
Columns to write
header : boolean or list of string, default True
Write out column names. If a list of string is given it is
assumed to be aliases for the column names
index : boolean, default True
Write row names (index)
index_label : string or sequence, default None
Column label for index column(s) if desired. If None is given, and
`header` and `index` are True, then the index names are used. A
sequence should be given if the DataFrame uses MultiIndex.
startrow : upper left cell row to dump data frame
startcol : upper left cell column to dump data frame
Notes
-----
Keyword arguments (and na_rep) are passed to the ``to_excel`` method
for each DataFrame written.
"""
from pandas.io.excel import ExcelWriter
if isinstance(path, str):
writer = ExcelWriter(path, engine=engine)
else:
writer = path
kwargs['na_rep'] = na_rep
for item, df in self.iteritems():
name = str(item)
df.to_excel(writer, name, **kwargs)
writer.save() |
Quickly retrieve single value at ( item major minor ) location. | def get_value(self, *args, **kwargs):
"""
Quickly retrieve single value at (item, major, minor) location.
.. deprecated:: 0.21.0
Please use .at[] or .iat[] accessors.
Parameters
----------
item : item label (panel item)
major : major axis label (panel item row)
minor : minor axis label (panel item column)
takeable : interpret the passed labels as indexers, default False
Returns
-------
value : scalar value
"""
warnings.warn("get_value is deprecated and will be removed "
"in a future release. Please use "
".at[] or .iat[] accessors instead", FutureWarning,
stacklevel=2)
return self._get_value(*args, **kwargs) |
Quickly set single value at ( item major minor ) location. | def set_value(self, *args, **kwargs):
"""
Quickly set single value at (item, major, minor) location.
.. deprecated:: 0.21.0
Please use .at[] or .iat[] accessors.
Parameters
----------
item : item label (panel item)
major : major axis label (panel item row)
minor : minor axis label (panel item column)
value : scalar
takeable : interpret the passed labels as indexers, default False
Returns
-------
panel : Panel
If label combo is contained, will be reference to calling Panel,
otherwise a new object.
"""
warnings.warn("set_value is deprecated and will be removed "
"in a future release. Please use "
".at[] or .iat[] accessors instead", FutureWarning,
stacklevel=2)
return self._set_value(*args, **kwargs) |
Unpickle the panel. | def _unpickle_panel_compat(self, state): # pragma: no cover
"""
Unpickle the panel.
"""
from pandas.io.pickle import _unpickle_array
_unpickle = _unpickle_array
vals, items, major, minor = state
items = _unpickle(items)
major = _unpickle(major)
minor = _unpickle(minor)
values = _unpickle(vals)
wp = Panel(values, items, major, minor)
self._data = wp._data |
Conform input DataFrame to align with chosen axis pair. | def conform(self, frame, axis='items'):
"""
Conform input DataFrame to align with chosen axis pair.
Parameters
----------
frame : DataFrame
axis : {'items', 'major', 'minor'}
Axis the input corresponds to. E.g., if axis='major', then
the frame's columns would be items, and the index would be
values of the minor axis
Returns
-------
DataFrame
"""
axes = self._get_plane_axes(axis)
return frame.reindex(**self._extract_axes_for_slice(self, axes)) |
Round each value in Panel to a specified number of decimal places. | def round(self, decimals=0, *args, **kwargs):
"""
Round each value in Panel to a specified number of decimal places.
.. versionadded:: 0.18.0
Parameters
----------
decimals : int
Number of decimal places to round to (default: 0).
If decimals is negative, it specifies the number of
positions to the left of the decimal point.
Returns
-------
Panel object
See Also
--------
numpy.around
"""
nv.validate_round(args, kwargs)
if is_integer(decimals):
result = np.apply_along_axis(np.round, 0, self.values)
return self._wrap_result(result, axis=0)
raise TypeError("decimals must be an integer") |
Drop 2D from panel holding passed axis constant. | def dropna(self, axis=0, how='any', inplace=False):
"""
Drop 2D from panel, holding passed axis constant.
Parameters
----------
axis : int, default 0
Axis to hold constant. E.g. axis=1 will drop major_axis entries
having a certain amount of NA data
how : {'all', 'any'}, default 'any'
'any': one or more values are NA in the DataFrame along the
axis. For 'all' they all must be.
inplace : bool, default False
If True, do operation inplace and return None.
Returns
-------
dropped : Panel
"""
axis = self._get_axis_number(axis)
values = self.values
mask = notna(values)
for ax in reversed(sorted(set(range(self._AXIS_LEN)) - {axis})):
mask = mask.sum(ax)
per_slice = np.prod(values.shape[:axis] + values.shape[axis + 1:])
if how == 'all':
cond = mask > 0
else:
cond = mask == per_slice
new_ax = self._get_axis(axis)[cond]
result = self.reindex_axis(new_ax, axis=axis)
if inplace:
self._update_inplace(result)
else:
return result |
Return slice of panel along selected axis. | def xs(self, key, axis=1):
"""
Return slice of panel along selected axis.
Parameters
----------
key : object
Label
axis : {'items', 'major', 'minor}, default 1/'major'
Returns
-------
y : ndim(self)-1
Notes
-----
xs is only for getting, not setting values.
MultiIndex Slicers is a generic way to get/set values on any level or
levels and is a superset of xs functionality, see
:ref:`MultiIndex Slicers <advanced.mi_slicers>`
"""
axis = self._get_axis_number(axis)
if axis == 0:
return self[key]
self._consolidate_inplace()
axis_number = self._get_axis_number(axis)
new_data = self._data.xs(key, axis=axis_number, copy=False)
result = self._construct_return_type(new_data)
copy = new_data.is_mixed_type
result._set_is_copy(self, copy=copy)
return result |
Parameters ---------- i: int slice or sequence of integers axis: int | def _ixs(self, i, axis=0):
"""
Parameters
----------
i : int, slice, or sequence of integers
axis : int
"""
ax = self._get_axis(axis)
key = ax[i]
# xs cannot handle a non-scalar key, so just reindex here
# if we have a multi-index and a single tuple, then its a reduction
# (GH 7516)
if not (isinstance(ax, MultiIndex) and isinstance(key, tuple)):
if is_list_like(key):
indexer = {self._get_axis_name(axis): key}
return self.reindex(**indexer)
# a reduction
if axis == 0:
values = self._data.iget(i)
return self._box_item_values(key, values)
# xs by position
self._consolidate_inplace()
new_data = self._data.xs(i, axis=axis, copy=True, takeable=True)
return self._construct_return_type(new_data) |
Transform wide format into long ( stacked ) format as DataFrame whose columns are the Panel s items and whose index is a MultiIndex formed of the Panel s major and minor axes. | def to_frame(self, filter_observations=True):
"""
Transform wide format into long (stacked) format as DataFrame whose
columns are the Panel's items and whose index is a MultiIndex formed
of the Panel's major and minor axes.
Parameters
----------
filter_observations : boolean, default True
Drop (major, minor) pairs without a complete set of observations
across all the items
Returns
-------
y : DataFrame
"""
_, N, K = self.shape
if filter_observations:
# shaped like the return DataFrame
mask = notna(self.values).all(axis=0)
# size = mask.sum()
selector = mask.ravel()
else:
# size = N * K
selector = slice(None, None)
data = {item: self[item].values.ravel()[selector]
for item in self.items}
def construct_multi_parts(idx, n_repeat, n_shuffle=1):
# Replicates and shuffles MultiIndex, returns individual attributes
codes = [np.repeat(x, n_repeat) for x in idx.codes]
# Assumes that each label is divisible by n_shuffle
codes = [x.reshape(n_shuffle, -1).ravel(order='F')
for x in codes]
codes = [x[selector] for x in codes]
levels = idx.levels
names = idx.names
return codes, levels, names
def construct_index_parts(idx, major=True):
levels = [idx]
if major:
codes = [np.arange(N).repeat(K)[selector]]
names = idx.name or 'major'
else:
codes = np.arange(K).reshape(1, K)[np.zeros(N, dtype=int)]
codes = [codes.ravel()[selector]]
names = idx.name or 'minor'
names = [names]
return codes, levels, names
if isinstance(self.major_axis, MultiIndex):
major_codes, major_levels, major_names = construct_multi_parts(
self.major_axis, n_repeat=K)
else:
major_codes, major_levels, major_names = construct_index_parts(
self.major_axis)
if isinstance(self.minor_axis, MultiIndex):
minor_codes, minor_levels, minor_names = construct_multi_parts(
self.minor_axis, n_repeat=N, n_shuffle=K)
else:
minor_codes, minor_levels, minor_names = construct_index_parts(
self.minor_axis, major=False)
levels = major_levels + minor_levels
codes = major_codes + minor_codes
names = major_names + minor_names
index = MultiIndex(levels=levels, codes=codes, names=names,
verify_integrity=False)
return DataFrame(data, index=index, columns=self.items) |
Apply function along axis ( or axes ) of the Panel. | def apply(self, func, axis='major', **kwargs):
"""
Apply function along axis (or axes) of the Panel.
Parameters
----------
func : function
Function to apply to each combination of 'other' axes
e.g. if axis = 'items', the combination of major_axis/minor_axis
will each be passed as a Series; if axis = ('items', 'major'),
DataFrames of items & major axis will be passed
axis : {'items', 'minor', 'major'}, or {0, 1, 2}, or a tuple with two
axes
**kwargs
Additional keyword arguments will be passed to the function.
Returns
-------
result : Panel, DataFrame, or Series
Examples
--------
Returns a Panel with the square root of each element
>>> p = pd.Panel(np.random.rand(4, 3, 2)) # doctest: +SKIP
>>> p.apply(np.sqrt)
Equivalent to p.sum(1), returning a DataFrame
>>> p.apply(lambda x: x.sum(), axis=1) # doctest: +SKIP
Equivalent to previous:
>>> p.apply(lambda x: x.sum(), axis='major') # doctest: +SKIP
Return the shapes of each DataFrame over axis 2 (i.e the shapes of
items x major), as a Series
>>> p.apply(lambda x: x.shape, axis=(0,1)) # doctest: +SKIP
"""
if kwargs and not isinstance(func, np.ufunc):
f = lambda x: func(x, **kwargs)
else:
f = func
# 2d-slabs
if isinstance(axis, (tuple, list)) and len(axis) == 2:
return self._apply_2d(f, axis=axis)
axis = self._get_axis_number(axis)
# try ufunc like
if isinstance(f, np.ufunc):
try:
with np.errstate(all='ignore'):
result = np.apply_along_axis(func, axis, self.values)
return self._wrap_result(result, axis=axis)
except (AttributeError):
pass
# 1d
return self._apply_1d(f, axis=axis) |
Handle 2 - d slices equiv to iterating over the other axis. | def _apply_2d(self, func, axis):
"""
Handle 2-d slices, equiv to iterating over the other axis.
"""
ndim = self.ndim
axis = [self._get_axis_number(a) for a in axis]
# construct slabs, in 2-d this is a DataFrame result
indexer_axis = list(range(ndim))
for a in axis:
indexer_axis.remove(a)
indexer_axis = indexer_axis[0]
slicer = [slice(None, None)] * ndim
ax = self._get_axis(indexer_axis)
results = []
for i, e in enumerate(ax):
slicer[indexer_axis] = i
sliced = self.iloc[tuple(slicer)]
obj = func(sliced)
results.append((e, obj))
return self._construct_return_type(dict(results)) |
Return the type for the ndim of the result. | def _construct_return_type(self, result, axes=None):
"""
Return the type for the ndim of the result.
"""
ndim = getattr(result, 'ndim', None)
# need to assume they are the same
if ndim is None:
if isinstance(result, dict):
ndim = getattr(list(result.values())[0], 'ndim', 0)
# have a dict, so top-level is +1 dim
if ndim != 0:
ndim += 1
# scalar
if ndim == 0:
return Series(result)
# same as self
elif self.ndim == ndim:
# return the construction dictionary for these axes
if axes is None:
return self._constructor(result)
return self._constructor(result, **self._construct_axes_dict())
# sliced
elif self.ndim == ndim + 1:
if axes is None:
return self._constructor_sliced(result)
return self._constructor_sliced(
result, **self._extract_axes_for_slice(self, axes))
raise ValueError('invalid _construct_return_type [self->{self}] '
'[result->{result}]'.format(self=self, result=result)) |
Return number of observations over requested axis. | def count(self, axis='major'):
"""
Return number of observations over requested axis.
Parameters
----------
axis : {'items', 'major', 'minor'} or {0, 1, 2}
Returns
-------
count : DataFrame
"""
i = self._get_axis_number(axis)
values = self.values
mask = np.isfinite(values)
result = mask.sum(axis=i, dtype='int64')
return self._wrap_result(result, axis) |
Shift index by desired number of periods with an optional time freq. | def shift(self, periods=1, freq=None, axis='major'):
"""
Shift index by desired number of periods with an optional time freq.
The shifted data will not include the dropped periods and the
shifted axis will be smaller than the original. This is different
from the behavior of DataFrame.shift()
Parameters
----------
periods : int
Number of periods to move, can be positive or negative
freq : DateOffset, timedelta, or time rule string, optional
axis : {'items', 'major', 'minor'} or {0, 1, 2}
Returns
-------
shifted : Panel
"""
if freq:
return self.tshift(periods, freq, axis=axis)
return super().slice_shift(periods, axis=axis) |
Join items with other Panel either on major and minor axes column. | def join(self, other, how='left', lsuffix='', rsuffix=''):
"""
Join items with other Panel either on major and minor axes column.
Parameters
----------
other : Panel or list of Panels
Index should be similar to one of the columns in this one
how : {'left', 'right', 'outer', 'inner'}
How to handle indexes of the two objects. Default: 'left'
for joining on index, None otherwise
* left: use calling frame's index
* right: use input frame's index
* outer: form union of indexes
* inner: use intersection of indexes
lsuffix : string
Suffix to use from left frame's overlapping columns
rsuffix : string
Suffix to use from right frame's overlapping columns
Returns
-------
joined : Panel
"""
from pandas.core.reshape.concat import concat
if isinstance(other, Panel):
join_major, join_minor = self._get_join_index(other, how)
this = self.reindex(major=join_major, minor=join_minor)
other = other.reindex(major=join_major, minor=join_minor)
merged_data = this._data.merge(other._data, lsuffix, rsuffix)
return self._constructor(merged_data)
else:
if lsuffix or rsuffix:
raise ValueError('Suffixes not supported when passing '
'multiple panels')
if how == 'left':
how = 'outer'
join_axes = [self.major_axis, self.minor_axis]
elif how == 'right':
raise ValueError('Right join not supported with multiple '
'panels')
else:
join_axes = None
return concat([self] + list(other), axis=0, join=how,
join_axes=join_axes, verify_integrity=True) |
Modify Panel in place using non - NA values from other Panel. | def update(self, other, join='left', overwrite=True, filter_func=None,
errors='ignore'):
"""
Modify Panel in place using non-NA values from other Panel.
May also use object coercible to Panel. Will align on items.
Parameters
----------
other : Panel, or object coercible to Panel
The object from which the caller will be udpated.
join : {'left', 'right', 'outer', 'inner'}, default 'left'
How individual DataFrames are joined.
overwrite : bool, default True
If True then overwrite values for common keys in the calling Panel.
filter_func : callable(1d-array) -> 1d-array<bool>, default None
Can choose to replace values other than NA. Return True for values
that should be updated.
errors : {'raise', 'ignore'}, default 'ignore'
If 'raise', will raise an error if a DataFrame and other both.
.. versionchanged :: 0.24.0
Changed from `raise_conflict=False|True`
to `errors='ignore'|'raise'`.
See Also
--------
DataFrame.update : Similar method for DataFrames.
dict.update : Similar method for dictionaries.
"""
if not isinstance(other, self._constructor):
other = self._constructor(other)
axis_name = self._info_axis_name
axis_values = self._info_axis
other = other.reindex(**{axis_name: axis_values})
for frame in axis_values:
self[frame].update(other[frame], join=join, overwrite=overwrite,
filter_func=filter_func, errors=errors) |
Return a list of the axis indices. | def _extract_axes(self, data, axes, **kwargs):
"""
Return a list of the axis indices.
"""
return [self._extract_axis(self, data, axis=i, **kwargs)
for i, a in enumerate(axes)] |
Return the slice dictionary for these axes. | def _extract_axes_for_slice(self, axes):
"""
Return the slice dictionary for these axes.
"""
return {self._AXIS_SLICEMAP[i]: a for i, a in
zip(self._AXIS_ORDERS[self._AXIS_LEN - len(axes):], axes)} |
Conform set of _constructor_sliced - like objects to either an intersection of indices/ columns or a union. | def _homogenize_dict(self, frames, intersect=True, dtype=None):
"""
Conform set of _constructor_sliced-like objects to either
an intersection of indices / columns or a union.
Parameters
----------
frames : dict
intersect : boolean, default True
Returns
-------
dict of aligned results & indices
"""
result = dict()
# caller differs dict/ODict, preserved type
if isinstance(frames, OrderedDict):
result = OrderedDict()
adj_frames = OrderedDict()
for k, v in frames.items():
if isinstance(v, dict):
adj_frames[k] = self._constructor_sliced(v)
else:
adj_frames[k] = v
axes = self._AXIS_ORDERS[1:]
axes_dict = {a: ax for a, ax in zip(axes, self._extract_axes(
self, adj_frames, axes, intersect=intersect))}
reindex_dict = {self._AXIS_SLICEMAP[a]: axes_dict[a] for a in axes}
reindex_dict['copy'] = False
for key, frame in adj_frames.items():
if frame is not None:
result[key] = frame.reindex(**reindex_dict)
else:
result[key] = None
axes_dict['data'] = result
axes_dict['dtype'] = dtype
return axes_dict |
For the particular label_list gets the offsets into the hypothetical list representing the totally ordered cartesian product of all possible label combinations * as long as * this space fits within int64 bounds ; otherwise though group indices identify unique combinations of labels they cannot be deconstructed. - If sort rank of returned ids preserve lexical ranks of labels. i. e. returned id s can be used to do lexical sort on labels ; - If xnull nulls ( - 1 labels ) are passed through. | def get_group_index(labels, shape, sort, xnull):
"""
For the particular label_list, gets the offsets into the hypothetical list
representing the totally ordered cartesian product of all possible label
combinations, *as long as* this space fits within int64 bounds;
otherwise, though group indices identify unique combinations of
labels, they cannot be deconstructed.
- If `sort`, rank of returned ids preserve lexical ranks of labels.
i.e. returned id's can be used to do lexical sort on labels;
- If `xnull` nulls (-1 labels) are passed through.
Parameters
----------
labels: sequence of arrays
Integers identifying levels at each location
shape: sequence of ints same length as labels
Number of unique levels at each location
sort: boolean
If the ranks of returned ids should match lexical ranks of labels
xnull: boolean
If true nulls are excluded. i.e. -1 values in the labels are
passed through
Returns
-------
An array of type int64 where two elements are equal if their corresponding
labels are equal at all location.
"""
def _int64_cut_off(shape):
acc = 1
for i, mul in enumerate(shape):
acc *= int(mul)
if not acc < _INT64_MAX:
return i
return len(shape)
def maybe_lift(lab, size):
# promote nan values (assigned -1 label in lab array)
# so that all output values are non-negative
return (lab + 1, size + 1) if (lab == -1).any() else (lab, size)
labels = map(ensure_int64, labels)
if not xnull:
labels, shape = map(list, zip(*map(maybe_lift, labels, shape)))
labels = list(labels)
shape = list(shape)
# Iteratively process all the labels in chunks sized so less
# than _INT64_MAX unique int ids will be required for each chunk
while True:
# how many levels can be done without overflow:
nlev = _int64_cut_off(shape)
# compute flat ids for the first `nlev` levels
stride = np.prod(shape[1:nlev], dtype='i8')
out = stride * labels[0].astype('i8', subok=False, copy=False)
for i in range(1, nlev):
if shape[i] == 0:
stride = 0
else:
stride //= shape[i]
out += labels[i] * stride
if xnull: # exclude nulls
mask = labels[0] == -1
for lab in labels[1:nlev]:
mask |= lab == -1
out[mask] = -1
if nlev == len(shape): # all levels done!
break
# compress what has been done so far in order to avoid overflow
# to retain lexical ranks, obs_ids should be sorted
comp_ids, obs_ids = compress_group_index(out, sort=sort)
labels = [comp_ids] + labels[nlev:]
shape = [len(obs_ids)] + shape[nlev:]
return out |
reconstruct labels from observed group ids | def decons_obs_group_ids(comp_ids, obs_ids, shape, labels, xnull):
"""
reconstruct labels from observed group ids
Parameters
----------
xnull: boolean,
if nulls are excluded; i.e. -1 labels are passed through
"""
if not xnull:
lift = np.fromiter(((a == -1).any() for a in labels), dtype='i8')
shape = np.asarray(shape, dtype='i8') + lift
if not is_int64_overflow_possible(shape):
# obs ids are deconstructable! take the fast route!
out = decons_group_index(obs_ids, shape)
return out if xnull or not lift.any() \
else [x - y for x, y in zip(out, lift)]
i = unique_label_indices(comp_ids)
i8copy = lambda a: a.astype('i8', subok=False, copy=True)
return [i8copy(lab[i]) for lab in labels] |
This is intended to be a drop - in replacement for np. argsort which handles NaNs. It adds ascending and na_position parameters. GH #6399 #5231 | def nargsort(items, kind='quicksort', ascending=True, na_position='last'):
"""
This is intended to be a drop-in replacement for np.argsort which
handles NaNs. It adds ascending and na_position parameters.
GH #6399, #5231
"""
# specially handle Categorical
if is_categorical_dtype(items):
if na_position not in {'first', 'last'}:
raise ValueError('invalid na_position: {!r}'.format(na_position))
mask = isna(items)
cnt_null = mask.sum()
sorted_idx = items.argsort(ascending=ascending, kind=kind)
if ascending and na_position == 'last':
# NaN is coded as -1 and is listed in front after sorting
sorted_idx = np.roll(sorted_idx, -cnt_null)
elif not ascending and na_position == 'first':
# NaN is coded as -1 and is listed in the end after sorting
sorted_idx = np.roll(sorted_idx, cnt_null)
return sorted_idx
with warnings.catch_warnings():
# https://github.com/pandas-dev/pandas/issues/25439
# can be removed once ExtensionArrays are properly handled by nargsort
warnings.filterwarnings(
"ignore", category=FutureWarning,
message="Converting timezone-aware DatetimeArray to")
items = np.asanyarray(items)
idx = np.arange(len(items))
mask = isna(items)
non_nans = items[~mask]
non_nan_idx = idx[~mask]
nan_idx = np.nonzero(mask)[0]
if not ascending:
non_nans = non_nans[::-1]
non_nan_idx = non_nan_idx[::-1]
indexer = non_nan_idx[non_nans.argsort(kind=kind)]
if not ascending:
indexer = indexer[::-1]
# Finally, place the NaNs at the end or the beginning according to
# na_position
if na_position == 'last':
indexer = np.concatenate([indexer, nan_idx])
elif na_position == 'first':
indexer = np.concatenate([nan_idx, indexer])
else:
raise ValueError('invalid na_position: {!r}'.format(na_position))
return indexer |
return a diction of { labels } - > { indexers } | def get_indexer_dict(label_list, keys):
""" return a diction of {labels} -> {indexers} """
shape = list(map(len, keys))
group_index = get_group_index(label_list, shape, sort=True, xnull=True)
ngroups = ((group_index.size and group_index.max()) + 1) \
if is_int64_overflow_possible(shape) \
else np.prod(shape, dtype='i8')
sorter = get_group_index_sorter(group_index, ngroups)
sorted_labels = [lab.take(sorter) for lab in label_list]
group_index = group_index.take(sorter)
return lib.indices_fast(sorter, group_index, keys, sorted_labels) |
algos. groupsort_indexer implements counting sort and it is at least O ( ngroups ) where ngroups = prod ( shape ) shape = map ( len keys ) that is linear in the number of combinations ( cartesian product ) of unique values of groupby keys. This can be huge when doing multi - key groupby. np. argsort ( kind = mergesort ) is O ( count x log ( count )) where count is the length of the data - frame ; Both algorithms are stable sort and that is necessary for correctness of groupby operations. e. g. consider: df. groupby ( key ) [ col ]. transform ( first ) | def get_group_index_sorter(group_index, ngroups):
"""
algos.groupsort_indexer implements `counting sort` and it is at least
O(ngroups), where
ngroups = prod(shape)
shape = map(len, keys)
that is, linear in the number of combinations (cartesian product) of unique
values of groupby keys. This can be huge when doing multi-key groupby.
np.argsort(kind='mergesort') is O(count x log(count)) where count is the
length of the data-frame;
Both algorithms are `stable` sort and that is necessary for correctness of
groupby operations. e.g. consider:
df.groupby(key)[col].transform('first')
"""
count = len(group_index)
alpha = 0.0 # taking complexities literally; there may be
beta = 1.0 # some room for fine-tuning these parameters
do_groupsort = (count > 0 and ((alpha + beta * ngroups) <
(count * np.log(count))))
if do_groupsort:
sorter, _ = algos.groupsort_indexer(ensure_int64(group_index),
ngroups)
return ensure_platform_int(sorter)
else:
return group_index.argsort(kind='mergesort') |
Group_index is offsets into cartesian product of all possible labels. This space can be huge so this function compresses it by computing offsets ( comp_ids ) into the list of unique labels ( obs_group_ids ). | def compress_group_index(group_index, sort=True):
"""
Group_index is offsets into cartesian product of all possible labels. This
space can be huge, so this function compresses it, by computing offsets
(comp_ids) into the list of unique labels (obs_group_ids).
"""
size_hint = min(len(group_index), hashtable._SIZE_HINT_LIMIT)
table = hashtable.Int64HashTable(size_hint)
group_index = ensure_int64(group_index)
# note, group labels come out ascending (ie, 1,2,3 etc)
comp_ids, obs_group_ids = table.get_labels_groupby(group_index)
if sort and len(obs_group_ids) > 0:
obs_group_ids, comp_ids = _reorder_by_uniques(obs_group_ids, comp_ids)
return comp_ids, obs_group_ids |
Sort values and reorder corresponding labels. values should be unique if labels is not None. Safe for use with mixed types ( int str ) orders ints before strs. | def safe_sort(values, labels=None, na_sentinel=-1, assume_unique=False):
"""
Sort ``values`` and reorder corresponding ``labels``.
``values`` should be unique if ``labels`` is not None.
Safe for use with mixed types (int, str), orders ints before strs.
.. versionadded:: 0.19.0
Parameters
----------
values : list-like
Sequence; must be unique if ``labels`` is not None.
labels : list_like
Indices to ``values``. All out of bound indices are treated as
"not found" and will be masked with ``na_sentinel``.
na_sentinel : int, default -1
Value in ``labels`` to mark "not found".
Ignored when ``labels`` is None.
assume_unique : bool, default False
When True, ``values`` are assumed to be unique, which can speed up
the calculation. Ignored when ``labels`` is None.
Returns
-------
ordered : ndarray
Sorted ``values``
new_labels : ndarray
Reordered ``labels``; returned when ``labels`` is not None.
Raises
------
TypeError
* If ``values`` is not list-like or if ``labels`` is neither None
nor list-like
* If ``values`` cannot be sorted
ValueError
* If ``labels`` is not None and ``values`` contain duplicates.
"""
if not is_list_like(values):
raise TypeError("Only list-like objects are allowed to be passed to"
"safe_sort as values")
if not isinstance(values, np.ndarray):
# don't convert to string types
dtype, _ = infer_dtype_from_array(values)
values = np.asarray(values, dtype=dtype)
def sort_mixed(values):
# order ints before strings, safe in py3
str_pos = np.array([isinstance(x, str) for x in values],
dtype=bool)
nums = np.sort(values[~str_pos])
strs = np.sort(values[str_pos])
return np.concatenate([nums, np.asarray(strs, dtype=object)])
sorter = None
if lib.infer_dtype(values, skipna=False) == 'mixed-integer':
# unorderable in py3 if mixed str/int
ordered = sort_mixed(values)
else:
try:
sorter = values.argsort()
ordered = values.take(sorter)
except TypeError:
# try this anyway
ordered = sort_mixed(values)
# labels:
if labels is None:
return ordered
if not is_list_like(labels):
raise TypeError("Only list-like objects or None are allowed to be"
"passed to safe_sort as labels")
labels = ensure_platform_int(np.asarray(labels))
from pandas import Index
if not assume_unique and not Index(values).is_unique:
raise ValueError("values should be unique if labels is not None")
if sorter is None:
# mixed types
(hash_klass, _), values = algorithms._get_data_algo(
values, algorithms._hashtables)
t = hash_klass(len(values))
t.map_locations(values)
sorter = ensure_platform_int(t.lookup(ordered))
reverse_indexer = np.empty(len(sorter), dtype=np.int_)
reverse_indexer.put(sorter, np.arange(len(sorter)))
mask = (labels < -len(values)) | (labels >= len(values)) | \
(labels == na_sentinel)
# (Out of bound indices will be masked with `na_sentinel` next, so we may
# deal with them here without performance loss using `mode='wrap'`.)
new_labels = reverse_indexer.take(labels, mode='wrap')
np.putmask(new_labels, mask, na_sentinel)
return ordered, ensure_platform_int(new_labels) |
Attempt to prevent foot - shooting in a helpful way. | def _check_ne_builtin_clash(expr):
"""Attempt to prevent foot-shooting in a helpful way.
Parameters
----------
terms : Term
Terms can contain
"""
names = expr.names
overlap = names & _ne_builtins
if overlap:
s = ', '.join(map(repr, overlap))
raise NumExprClobberingError('Variables in expression "{expr}" '
'overlap with builtins: ({s})'
.format(expr=expr, s=s)) |
Run the engine on the expression | def evaluate(self):
"""Run the engine on the expression
This method performs alignment which is necessary no matter what engine
is being used, thus its implementation is in the base class.
Returns
-------
obj : object
The result of the passed expression.
"""
if not self._is_aligned:
self.result_type, self.aligned_axes = _align(self.expr.terms)
# make sure no names in resolvers and locals/globals clash
res = self._evaluate()
return _reconstruct_object(self.result_type, res, self.aligned_axes,
self.expr.terms.return_type) |
Find the appropriate Block subclass to use for the given values and dtype. | def get_block_type(values, dtype=None):
"""
Find the appropriate Block subclass to use for the given values and dtype.
Parameters
----------
values : ndarray-like
dtype : numpy or pandas dtype
Returns
-------
cls : class, subclass of Block
"""
dtype = dtype or values.dtype
vtype = dtype.type
if is_sparse(dtype):
# Need this first(ish) so that Sparse[datetime] is sparse
cls = ExtensionBlock
elif is_categorical(values):
cls = CategoricalBlock
elif issubclass(vtype, np.datetime64):
assert not is_datetime64tz_dtype(values)
cls = DatetimeBlock
elif is_datetime64tz_dtype(values):
cls = DatetimeTZBlock
elif is_interval_dtype(dtype) or is_period_dtype(dtype):
cls = ObjectValuesExtensionBlock
elif is_extension_array_dtype(values):
cls = ExtensionBlock
elif issubclass(vtype, np.floating):
cls = FloatBlock
elif issubclass(vtype, np.timedelta64):
assert issubclass(vtype, np.integer)
cls = TimeDeltaBlock
elif issubclass(vtype, np.complexfloating):
cls = ComplexBlock
elif issubclass(vtype, np.integer):
cls = IntBlock
elif dtype == np.bool_:
cls = BoolBlock
else:
cls = ObjectBlock
return cls |
return a new extended blocks givin the result | def _extend_blocks(result, blocks=None):
""" return a new extended blocks, givin the result """
from pandas.core.internals import BlockManager
if blocks is None:
blocks = []
if isinstance(result, list):
for r in result:
if isinstance(r, list):
blocks.extend(r)
else:
blocks.append(r)
elif isinstance(result, BlockManager):
blocks.extend(result.blocks)
else:
blocks.append(result)
return blocks |
guarantee the shape of the values to be at least 1 d | def _block_shape(values, ndim=1, shape=None):
""" guarantee the shape of the values to be at least 1 d """
if values.ndim < ndim:
if shape is None:
shape = values.shape
if not is_extension_array_dtype(values):
# TODO: https://github.com/pandas-dev/pandas/issues/23023
# block.shape is incorrect for "2D" ExtensionArrays
# We can't, and don't need to, reshape.
values = values.reshape(tuple((1, ) + shape))
return values |
If possible reshape arr to have shape new_shape with a couple of exceptions ( see gh - 13012 ): | def _safe_reshape(arr, new_shape):
"""
If possible, reshape `arr` to have shape `new_shape`,
with a couple of exceptions (see gh-13012):
1) If `arr` is a ExtensionArray or Index, `arr` will be
returned as is.
2) If `arr` is a Series, the `_values` attribute will
be reshaped and returned.
Parameters
----------
arr : array-like, object to be reshaped
new_shape : int or tuple of ints, the new shape
"""
if isinstance(arr, ABCSeries):
arr = arr._values
if not isinstance(arr, ABCExtensionArray):
arr = arr.reshape(new_shape)
return arr |
Return a new ndarray try to preserve dtype if possible. | def _putmask_smart(v, m, n):
"""
Return a new ndarray, try to preserve dtype if possible.
Parameters
----------
v : `values`, updated in-place (array like)
m : `mask`, applies to both sides (array like)
n : `new values` either scalar or an array like aligned with `values`
Returns
-------
values : ndarray with updated values
this *may* be a copy of the original
See Also
--------
ndarray.putmask
"""
# we cannot use np.asarray() here as we cannot have conversions
# that numpy does when numeric are mixed with strings
# n should be the length of the mask or a scalar here
if not is_list_like(n):
n = np.repeat(n, len(m))
elif isinstance(n, np.ndarray) and n.ndim == 0: # numpy scalar
n = np.repeat(np.array(n, ndmin=1), len(m))
# see if we are only masking values that if putted
# will work in the current dtype
try:
nn = n[m]
# make sure that we have a nullable type
# if we have nulls
if not _isna_compat(v, nn[0]):
raise ValueError
# we ignore ComplexWarning here
with warnings.catch_warnings(record=True):
warnings.simplefilter("ignore", np.ComplexWarning)
nn_at = nn.astype(v.dtype)
# avoid invalid dtype comparisons
# between numbers & strings
# only compare integers/floats
# don't compare integers to datetimelikes
if (not is_numeric_v_string_like(nn, nn_at) and
(is_float_dtype(nn.dtype) or
is_integer_dtype(nn.dtype) and
is_float_dtype(nn_at.dtype) or
is_integer_dtype(nn_at.dtype))):
comp = (nn == nn_at)
if is_list_like(comp) and comp.all():
nv = v.copy()
nv[m] = nn_at
return nv
except (ValueError, IndexError, TypeError, OverflowError):
pass
n = np.asarray(n)
def _putmask_preserve(nv, n):
try:
nv[m] = n[m]
except (IndexError, ValueError):
nv[m] = n
return nv
# preserves dtype if possible
if v.dtype.kind == n.dtype.kind:
return _putmask_preserve(v, n)
# change the dtype if needed
dtype, _ = maybe_promote(n.dtype)
if is_extension_type(v.dtype) and is_object_dtype(dtype):
v = v.get_values(dtype)
else:
v = v.astype(dtype)
return _putmask_preserve(v, n) |
ndim inference and validation. | def _check_ndim(self, values, ndim):
"""
ndim inference and validation.
Infers ndim from 'values' if not provided to __init__.
Validates that values.ndim and ndim are consistent if and only if
the class variable '_validate_ndim' is True.
Parameters
----------
values : array-like
ndim : int or None
Returns
-------
ndim : int
Raises
------
ValueError : the number of dimensions do not match
"""
if ndim is None:
ndim = values.ndim
if self._validate_ndim and values.ndim != ndim:
msg = ("Wrong number of dimensions. values.ndim != ndim "
"[{} != {}]")
raise ValueError(msg.format(values.ndim, ndim))
return ndim |
validate that we have a astypeable to categorical returns a boolean if we are a categorical | def is_categorical_astype(self, dtype):
"""
validate that we have a astypeable to categorical,
returns a boolean if we are a categorical
"""
if dtype is Categorical or dtype is CategoricalDtype:
# this is a pd.Categorical, but is not
# a valid type for astypeing
raise TypeError("invalid type {0} for astype".format(dtype))
elif is_categorical_dtype(dtype):
return True
return False |
return an internal format currently just the ndarray this is often overridden to handle to_dense like operations | def get_values(self, dtype=None):
"""
return an internal format, currently just the ndarray
this is often overridden to handle to_dense like operations
"""
if is_object_dtype(dtype):
return self.values.astype(object)
return self.values |
Create a new block with type inference propagate any values that are not specified | def make_block(self, values, placement=None, ndim=None):
"""
Create a new block, with type inference propagate any values that are
not specified
"""
if placement is None:
placement = self.mgr_locs
if ndim is None:
ndim = self.ndim
return make_block(values, placement=placement, ndim=ndim) |
Wrap given values in a block of same type as self. | def make_block_same_class(self, values, placement=None, ndim=None,
dtype=None):
""" Wrap given values in a block of same type as self. """
if dtype is not None:
# issue 19431 fastparquet is passing this
warnings.warn("dtype argument is deprecated, will be removed "
"in a future release.", DeprecationWarning)
if placement is None:
placement = self.mgr_locs
return make_block(values, placement=placement, ndim=ndim,
klass=self.__class__, dtype=dtype) |
Perform __getitem__ - like return result as block. | def getitem_block(self, slicer, new_mgr_locs=None):
"""
Perform __getitem__-like, return result as block.
As of now, only supports slices that preserve dimensionality.
"""
if new_mgr_locs is None:
if isinstance(slicer, tuple):
axis0_slicer = slicer[0]
else:
axis0_slicer = slicer
new_mgr_locs = self.mgr_locs[axis0_slicer]
new_values = self._slice(slicer)
if self._validate_ndim and new_values.ndim != self.ndim:
raise ValueError("Only same dim slicing is allowed")
return self.make_block_same_class(new_values, new_mgr_locs) |
Concatenate list of single blocks of the same type. | def concat_same_type(self, to_concat, placement=None):
"""
Concatenate list of single blocks of the same type.
"""
values = self._concatenator([blk.values for blk in to_concat],
axis=self.ndim - 1)
return self.make_block_same_class(
values, placement=placement or slice(0, len(values), 1)) |
Delete given loc ( - s ) from block in - place. | def delete(self, loc):
"""
Delete given loc(-s) from block in-place.
"""
self.values = np.delete(self.values, loc, 0)
self.mgr_locs = self.mgr_locs.delete(loc) |
apply the function to my values ; return a block if we are not one | def apply(self, func, **kwargs):
""" apply the function to my values; return a block if we are not
one
"""
with np.errstate(all='ignore'):
result = func(self.values, **kwargs)
if not isinstance(result, Block):
result = self.make_block(values=_block_shape(result,
ndim=self.ndim))
return result |
fillna on the block with the value. If we fail then convert to ObjectBlock and try again | def fillna(self, value, limit=None, inplace=False, downcast=None):
""" fillna on the block with the value. If we fail, then convert to
ObjectBlock and try again
"""
inplace = validate_bool_kwarg(inplace, 'inplace')
if not self._can_hold_na:
if inplace:
return self
else:
return self.copy()
mask = isna(self.values)
if limit is not None:
if not is_integer(limit):
raise ValueError('Limit must be an integer')
if limit < 1:
raise ValueError('Limit must be greater than 0')
if self.ndim > 2:
raise NotImplementedError("number of dimensions for 'fillna' "
"is currently limited to 2")
mask[mask.cumsum(self.ndim - 1) > limit] = False
# fillna, but if we cannot coerce, then try again as an ObjectBlock
try:
values, _ = self._try_coerce_args(self.values, value)
blocks = self.putmask(mask, value, inplace=inplace)
blocks = [b.make_block(values=self._try_coerce_result(b.values))
for b in blocks]
return self._maybe_downcast(blocks, downcast)
except (TypeError, ValueError):
# we can't process the value, but nothing to do
if not mask.any():
return self if inplace else self.copy()
# operate column-by-column
def f(m, v, i):
block = self.coerce_to_target_dtype(value)
# slice out our block
if i is not None:
block = block.getitem_block(slice(i, i + 1))
return block.fillna(value,
limit=limit,
inplace=inplace,
downcast=None)
return self.split_and_operate(mask, f, inplace) |
split the block per - column and apply the callable f per - column return a new block for each. Handle masking which will not change a block unless needed. | def split_and_operate(self, mask, f, inplace):
"""
split the block per-column, and apply the callable f
per-column, return a new block for each. Handle
masking which will not change a block unless needed.
Parameters
----------
mask : 2-d boolean mask
f : callable accepting (1d-mask, 1d values, indexer)
inplace : boolean
Returns
-------
list of blocks
"""
if mask is None:
mask = np.ones(self.shape, dtype=bool)
new_values = self.values
def make_a_block(nv, ref_loc):
if isinstance(nv, Block):
block = nv
elif isinstance(nv, list):
block = nv[0]
else:
# Put back the dimension that was taken from it and make
# a block out of the result.
try:
nv = _block_shape(nv, ndim=self.ndim)
except (AttributeError, NotImplementedError):
pass
block = self.make_block(values=nv,
placement=ref_loc)
return block
# ndim == 1
if self.ndim == 1:
if mask.any():
nv = f(mask, new_values, None)
else:
nv = new_values if inplace else new_values.copy()
block = make_a_block(nv, self.mgr_locs)
return [block]
# ndim > 1
new_blocks = []
for i, ref_loc in enumerate(self.mgr_locs):
m = mask[i]
v = new_values[i]
# need a new block
if m.any():
nv = f(m, v, i)
else:
nv = v if inplace else v.copy()
block = make_a_block(nv, [ref_loc])
new_blocks.append(block)
return new_blocks |
try to downcast each item to the dict of dtypes if present | def downcast(self, dtypes=None):
""" try to downcast each item to the dict of dtypes if present """
# turn it off completely
if dtypes is False:
return self
values = self.values
# single block handling
if self._is_single_block:
# try to cast all non-floats here
if dtypes is None:
dtypes = 'infer'
nv = maybe_downcast_to_dtype(values, dtypes)
return self.make_block(nv)
# ndim > 1
if dtypes is None:
return self
if not (dtypes == 'infer' or isinstance(dtypes, dict)):
raise ValueError("downcast must have a dictionary or 'infer' as "
"its argument")
# operate column-by-column
# this is expensive as it splits the blocks items-by-item
def f(m, v, i):
if dtypes == 'infer':
dtype = 'infer'
else:
raise AssertionError("dtypes as dict is not supported yet")
if dtype is not None:
v = maybe_downcast_to_dtype(v, dtype)
return v
return self.split_and_operate(None, f, False) |
Coerce to the new type | def _astype(self, dtype, copy=False, errors='raise', values=None,
**kwargs):
"""Coerce to the new type
Parameters
----------
dtype : str, dtype convertible
copy : boolean, default False
copy if indicated
errors : str, {'raise', 'ignore'}, default 'ignore'
- ``raise`` : allow exceptions to be raised
- ``ignore`` : suppress exceptions. On error return original object
Returns
-------
Block
"""
errors_legal_values = ('raise', 'ignore')
if errors not in errors_legal_values:
invalid_arg = ("Expected value of kwarg 'errors' to be one of {}. "
"Supplied value is '{}'".format(
list(errors_legal_values), errors))
raise ValueError(invalid_arg)
if (inspect.isclass(dtype) and
issubclass(dtype, (PandasExtensionDtype, ExtensionDtype))):
msg = ("Expected an instance of {}, but got the class instead. "
"Try instantiating 'dtype'.".format(dtype.__name__))
raise TypeError(msg)
# may need to convert to categorical
if self.is_categorical_astype(dtype):
# deprecated 17636
if ('categories' in kwargs or 'ordered' in kwargs):
if isinstance(dtype, CategoricalDtype):
raise TypeError(
"Cannot specify a CategoricalDtype and also "
"`categories` or `ordered`. Use "
"`dtype=CategoricalDtype(categories, ordered)`"
" instead.")
warnings.warn("specifying 'categories' or 'ordered' in "
".astype() is deprecated; pass a "
"CategoricalDtype instead",
FutureWarning, stacklevel=7)
categories = kwargs.get('categories', None)
ordered = kwargs.get('ordered', None)
if com._any_not_none(categories, ordered):
dtype = CategoricalDtype(categories, ordered)
if is_categorical_dtype(self.values):
# GH 10696/18593: update an existing categorical efficiently
return self.make_block(self.values.astype(dtype, copy=copy))
return self.make_block(Categorical(self.values, dtype=dtype))
dtype = pandas_dtype(dtype)
# astype processing
if is_dtype_equal(self.dtype, dtype):
if copy:
return self.copy()
return self
try:
# force the copy here
if values is None:
if self.is_extension:
values = self.values.astype(dtype)
else:
if issubclass(dtype.type, str):
# use native type formatting for datetime/tz/timedelta
if self.is_datelike:
values = self.to_native_types()
# astype formatting
else:
values = self.get_values()
else:
values = self.get_values(dtype=dtype)
# _astype_nansafe works fine with 1-d only
values = astype_nansafe(values.ravel(), dtype, copy=True)
# TODO(extension)
# should we make this attribute?
try:
values = values.reshape(self.shape)
except AttributeError:
pass
newb = make_block(values, placement=self.mgr_locs,
ndim=self.ndim)
except Exception: # noqa: E722
if errors == 'raise':
raise
newb = self.copy() if copy else self
if newb.is_numeric and self.is_numeric:
if newb.shape != self.shape:
raise TypeError(
"cannot set astype for copy = [{copy}] for dtype "
"({dtype} [{shape}]) to different shape "
"({newb_dtype} [{newb_shape}])".format(
copy=copy, dtype=self.dtype.name,
shape=self.shape, newb_dtype=newb.dtype.name,
newb_shape=newb.shape))
return newb |
require the same dtype as ourselves | def _can_hold_element(self, element):
""" require the same dtype as ourselves """
dtype = self.values.dtype.type
tipo = maybe_infer_dtype_type(element)
if tipo is not None:
return issubclass(tipo.type, dtype)
return isinstance(element, dtype) |
try to cast the result to our original type we may have roundtripped thru object in the mean - time | def _try_cast_result(self, result, dtype=None):
""" try to cast the result to our original type, we may have
roundtripped thru object in the mean-time
"""
if dtype is None:
dtype = self.dtype
if self.is_integer or self.is_bool or self.is_datetime:
pass
elif self.is_float and result.dtype == self.dtype:
# protect against a bool/object showing up here
if isinstance(dtype, str) and dtype == 'infer':
return result
if not isinstance(dtype, type):
dtype = dtype.type
if issubclass(dtype, (np.bool_, np.object_)):
if issubclass(dtype, np.bool_):
if isna(result).all():
return result.astype(np.bool_)
else:
result = result.astype(np.object_)
result[result == 1] = True
result[result == 0] = False
return result
else:
return result.astype(np.object_)
return result
# may need to change the dtype here
return maybe_downcast_to_dtype(result, dtype) |
provide coercion to our input arguments | def _try_coerce_args(self, values, other):
""" provide coercion to our input arguments """
if np.any(notna(other)) and not self._can_hold_element(other):
# coercion issues
# let higher levels handle
raise TypeError("cannot convert {} to an {}".format(
type(other).__name__,
type(self).__name__.lower().replace('Block', '')))
return values, other |
convert to our native types format slicing if desired | def to_native_types(self, slicer=None, na_rep='nan', quoting=None,
**kwargs):
""" convert to our native types format, slicing if desired """
values = self.get_values()
if slicer is not None:
values = values[:, slicer]
mask = isna(values)
if not self.is_object and not quoting:
values = values.astype(str)
else:
values = np.array(values, dtype='object')
values[mask] = na_rep
return values |
copy constructor | def copy(self, deep=True):
""" copy constructor """
values = self.values
if deep:
values = values.copy()
return self.make_block_same_class(values, ndim=self.ndim) |
replace the to_replace value with value possible to create new blocks here this is just a call to putmask. regex is not used here. It is used in ObjectBlocks. It is here for API compatibility. | def replace(self, to_replace, value, inplace=False, filter=None,
regex=False, convert=True):
"""replace the to_replace value with value, possible to create new
blocks here this is just a call to putmask. regex is not used here.
It is used in ObjectBlocks. It is here for API compatibility.
"""
inplace = validate_bool_kwarg(inplace, 'inplace')
original_to_replace = to_replace
# try to replace, if we raise an error, convert to ObjectBlock and
# retry
try:
values, to_replace = self._try_coerce_args(self.values,
to_replace)
mask = missing.mask_missing(values, to_replace)
if filter is not None:
filtered_out = ~self.mgr_locs.isin(filter)
mask[filtered_out.nonzero()[0]] = False
blocks = self.putmask(mask, value, inplace=inplace)
if convert:
blocks = [b.convert(by_item=True, numeric=False,
copy=not inplace) for b in blocks]
return blocks
except (TypeError, ValueError):
# GH 22083, TypeError or ValueError occurred within error handling
# causes infinite loop. Cast and retry only if not objectblock.
if is_object_dtype(self):
raise
# try again with a compatible block
block = self.astype(object)
return block.replace(to_replace=original_to_replace,
value=value,
inplace=inplace,
filter=filter,
regex=regex,
convert=convert) |
Set the value inplace returning a a maybe different typed block. | def setitem(self, indexer, value):
"""Set the value inplace, returning a a maybe different typed block.
Parameters
----------
indexer : tuple, list-like, array-like, slice
The subset of self.values to set
value : object
The value being set
Returns
-------
Block
Notes
-----
`indexer` is a direct slice/positional indexer. `value` must
be a compatible shape.
"""
# coerce None values, if appropriate
if value is None:
if self.is_numeric:
value = np.nan
# coerce if block dtype can store value
values = self.values
try:
values, value = self._try_coerce_args(values, value)
# can keep its own dtype
if hasattr(value, 'dtype') and is_dtype_equal(values.dtype,
value.dtype):
dtype = self.dtype
else:
dtype = 'infer'
except (TypeError, ValueError):
# current dtype cannot store value, coerce to common dtype
find_dtype = False
if hasattr(value, 'dtype'):
dtype = value.dtype
find_dtype = True
elif lib.is_scalar(value):
if isna(value):
# NaN promotion is handled in latter path
dtype = False
else:
dtype, _ = infer_dtype_from_scalar(value,
pandas_dtype=True)
find_dtype = True
else:
dtype = 'infer'
if find_dtype:
dtype = find_common_type([values.dtype, dtype])
if not is_dtype_equal(self.dtype, dtype):
b = self.astype(dtype)
return b.setitem(indexer, value)
# value must be storeable at this moment
arr_value = np.array(value)
# cast the values to a type that can hold nan (if necessary)
if not self._can_hold_element(value):
dtype, _ = maybe_promote(arr_value.dtype)
values = values.astype(dtype)
transf = (lambda x: x.T) if self.ndim == 2 else (lambda x: x)
values = transf(values)
# length checking
check_setitem_lengths(indexer, value, values)
def _is_scalar_indexer(indexer):
# return True if we are all scalar indexers
if arr_value.ndim == 1:
if not isinstance(indexer, tuple):
indexer = tuple([indexer])
return any(isinstance(idx, np.ndarray) and len(idx) == 0
for idx in indexer)
return False
def _is_empty_indexer(indexer):
# return a boolean if we have an empty indexer
if is_list_like(indexer) and not len(indexer):
return True
if arr_value.ndim == 1:
if not isinstance(indexer, tuple):
indexer = tuple([indexer])
return any(isinstance(idx, np.ndarray) and len(idx) == 0
for idx in indexer)
return False
# empty indexers
# 8669 (empty)
if _is_empty_indexer(indexer):
pass
# setting a single element for each dim and with a rhs that could
# be say a list
# GH 6043
elif _is_scalar_indexer(indexer):
values[indexer] = value
# if we are an exact match (ex-broadcasting),
# then use the resultant dtype
elif (len(arr_value.shape) and
arr_value.shape[0] == values.shape[0] and
np.prod(arr_value.shape) == np.prod(values.shape)):
values[indexer] = value
try:
values = values.astype(arr_value.dtype)
except ValueError:
pass
# set
else:
values[indexer] = value
# coerce and try to infer the dtypes of the result
values = self._try_coerce_and_cast_result(values, dtype)
block = self.make_block(transf(values))
return block |
putmask the data to the block ; it is possible that we may create a new dtype of block | def putmask(self, mask, new, align=True, inplace=False, axis=0,
transpose=False):
""" putmask the data to the block; it is possible that we may create a
new dtype of block
return the resulting block(s)
Parameters
----------
mask : the condition to respect
new : a ndarray/object
align : boolean, perform alignment on other/cond, default is True
inplace : perform inplace modification, default is False
axis : int
transpose : boolean
Set to True if self is stored with axes reversed
Returns
-------
a list of new blocks, the result of the putmask
"""
new_values = self.values if inplace else self.values.copy()
new = getattr(new, 'values', new)
mask = getattr(mask, 'values', mask)
# if we are passed a scalar None, convert it here
if not is_list_like(new) and isna(new) and not self.is_object:
new = self.fill_value
if self._can_hold_element(new):
_, new = self._try_coerce_args(new_values, new)
if transpose:
new_values = new_values.T
# If the default repeat behavior in np.putmask would go in the
# wrong direction, then explicitly repeat and reshape new instead
if getattr(new, 'ndim', 0) >= 1:
if self.ndim - 1 == new.ndim and axis == 1:
new = np.repeat(
new, new_values.shape[-1]).reshape(self.shape)
new = new.astype(new_values.dtype)
# we require exact matches between the len of the
# values we are setting (or is compat). np.putmask
# doesn't check this and will simply truncate / pad
# the output, but we want sane error messages
#
# TODO: this prob needs some better checking
# for 2D cases
if ((is_list_like(new) and
np.any(mask[mask]) and
getattr(new, 'ndim', 1) == 1)):
if not (mask.shape[-1] == len(new) or
mask[mask].shape[-1] == len(new) or
len(new) == 1):
raise ValueError("cannot assign mismatch "
"length to masked array")
np.putmask(new_values, mask, new)
# maybe upcast me
elif mask.any():
if transpose:
mask = mask.T
if isinstance(new, np.ndarray):
new = new.T
axis = new_values.ndim - axis - 1
# Pseudo-broadcast
if getattr(new, 'ndim', 0) >= 1:
if self.ndim - 1 == new.ndim:
new_shape = list(new.shape)
new_shape.insert(axis, 1)
new = new.reshape(tuple(new_shape))
# operate column-by-column
def f(m, v, i):
if i is None:
# ndim==1 case.
n = new
else:
if isinstance(new, np.ndarray):
n = np.squeeze(new[i % new.shape[0]])
else:
n = np.array(new)
# type of the new block
dtype, _ = maybe_promote(n.dtype)
# we need to explicitly astype here to make a copy
n = n.astype(dtype)
nv = _putmask_smart(v, m, n)
return nv
new_blocks = self.split_and_operate(mask, f, inplace)
return new_blocks
if inplace:
return [self]
if transpose:
new_values = new_values.T
return [self.make_block(new_values)] |
coerce the current block to a dtype compat for other we will return a block possibly object and not raise | def coerce_to_target_dtype(self, other):
"""
coerce the current block to a dtype compat for other
we will return a block, possibly object, and not raise
we can also safely try to coerce to the same dtype
and will receive the same block
"""
# if we cannot then coerce to object
dtype, _ = infer_dtype_from(other, pandas_dtype=True)
if is_dtype_equal(self.dtype, dtype):
return self
if self.is_bool or is_object_dtype(dtype) or is_bool_dtype(dtype):
# we don't upcast to bool
return self.astype(object)
elif ((self.is_float or self.is_complex) and
(is_integer_dtype(dtype) or is_float_dtype(dtype))):
# don't coerce float/complex to int
return self
elif (self.is_datetime or
is_datetime64_dtype(dtype) or
is_datetime64tz_dtype(dtype)):
# not a datetime
if not ((is_datetime64_dtype(dtype) or
is_datetime64tz_dtype(dtype)) and self.is_datetime):
return self.astype(object)
# don't upcast timezone with different timezone or no timezone
mytz = getattr(self.dtype, 'tz', None)
othertz = getattr(dtype, 'tz', None)
if str(mytz) != str(othertz):
return self.astype(object)
raise AssertionError("possible recursion in "
"coerce_to_target_dtype: {} {}".format(
self, other))
elif (self.is_timedelta or is_timedelta64_dtype(dtype)):
# not a timedelta
if not (is_timedelta64_dtype(dtype) and self.is_timedelta):
return self.astype(object)
raise AssertionError("possible recursion in "
"coerce_to_target_dtype: {} {}".format(
self, other))
try:
return self.astype(dtype)
except (ValueError, TypeError, OverflowError):
pass
return self.astype(object) |
fillna but using the interpolate machinery | def _interpolate_with_fill(self, method='pad', axis=0, inplace=False,
limit=None, fill_value=None, coerce=False,
downcast=None):
""" fillna but using the interpolate machinery """
inplace = validate_bool_kwarg(inplace, 'inplace')
# if we are coercing, then don't force the conversion
# if the block can't hold the type
if coerce:
if not self._can_hold_na:
if inplace:
return [self]
else:
return [self.copy()]
values = self.values if inplace else self.values.copy()
values, fill_value = self._try_coerce_args(values, fill_value)
values = missing.interpolate_2d(values, method=method, axis=axis,
limit=limit, fill_value=fill_value,
dtype=self.dtype)
values = self._try_coerce_result(values)
blocks = [self.make_block_same_class(values, ndim=self.ndim)]
return self._maybe_downcast(blocks, downcast) |
interpolate using scipy wrappers | def _interpolate(self, method=None, index=None, values=None,
fill_value=None, axis=0, limit=None,
limit_direction='forward', limit_area=None,
inplace=False, downcast=None, **kwargs):
""" interpolate using scipy wrappers """
inplace = validate_bool_kwarg(inplace, 'inplace')
data = self.values if inplace else self.values.copy()
# only deal with floats
if not self.is_float:
if not self.is_integer:
return self
data = data.astype(np.float64)
if fill_value is None:
fill_value = self.fill_value
if method in ('krogh', 'piecewise_polynomial', 'pchip'):
if not index.is_monotonic:
raise ValueError("{0} interpolation requires that the "
"index be monotonic.".format(method))
# process 1-d slices in the axis direction
def func(x):
# process a 1-d slice, returning it
# should the axis argument be handled below in apply_along_axis?
# i.e. not an arg to missing.interpolate_1d
return missing.interpolate_1d(index, x, method=method, limit=limit,
limit_direction=limit_direction,
limit_area=limit_area,
fill_value=fill_value,
bounds_error=False, **kwargs)
# interp each column independently
interp_values = np.apply_along_axis(func, axis, data)
blocks = [self.make_block_same_class(interp_values)]
return self._maybe_downcast(blocks, downcast) |
Take values according to indexer and return them as a block. bb | def take_nd(self, indexer, axis, new_mgr_locs=None, fill_tuple=None):
"""
Take values according to indexer and return them as a block.bb
"""
# algos.take_nd dispatches for DatetimeTZBlock, CategoricalBlock
# so need to preserve types
# sparse is treated like an ndarray, but needs .get_values() shaping
values = self.values
if self.is_sparse:
values = self.get_values()
if fill_tuple is None:
fill_value = self.fill_value
new_values = algos.take_nd(values, indexer, axis=axis,
allow_fill=False, fill_value=fill_value)
else:
fill_value = fill_tuple[0]
new_values = algos.take_nd(values, indexer, axis=axis,
allow_fill=True, fill_value=fill_value)
if new_mgr_locs is None:
if axis == 0:
slc = libinternals.indexer_as_slice(indexer)
if slc is not None:
new_mgr_locs = self.mgr_locs[slc]
else:
new_mgr_locs = self.mgr_locs[indexer]
else:
new_mgr_locs = self.mgr_locs
if not is_dtype_equal(new_values.dtype, self.dtype):
return self.make_block(new_values, new_mgr_locs)
else:
return self.make_block_same_class(new_values, new_mgr_locs) |
return block for the diff of the values | def diff(self, n, axis=1):
""" return block for the diff of the values """
new_values = algos.diff(self.values, n, axis=axis)
return [self.make_block(values=new_values)] |
shift the block by periods possibly upcast | def shift(self, periods, axis=0, fill_value=None):
""" shift the block by periods, possibly upcast """
# convert integer to float if necessary. need to do a lot more than
# that, handle boolean etc also
new_values, fill_value = maybe_upcast(self.values, fill_value)
# make sure array sent to np.roll is c_contiguous
f_ordered = new_values.flags.f_contiguous
if f_ordered:
new_values = new_values.T
axis = new_values.ndim - axis - 1
if np.prod(new_values.shape):
new_values = np.roll(new_values, ensure_platform_int(periods),
axis=axis)
axis_indexer = [slice(None)] * self.ndim
if periods > 0:
axis_indexer[axis] = slice(None, periods)
else:
axis_indexer[axis] = slice(periods, None)
new_values[tuple(axis_indexer)] = fill_value
# restore original order
if f_ordered:
new_values = new_values.T
return [self.make_block(new_values)] |
evaluate the block ; return result block ( s ) from the result | def where(self, other, cond, align=True, errors='raise',
try_cast=False, axis=0, transpose=False):
"""
evaluate the block; return result block(s) from the result
Parameters
----------
other : a ndarray/object
cond : the condition to respect
align : boolean, perform alignment on other/cond
errors : str, {'raise', 'ignore'}, default 'raise'
- ``raise`` : allow exceptions to be raised
- ``ignore`` : suppress exceptions. On error return original object
axis : int
transpose : boolean
Set to True if self is stored with axes reversed
Returns
-------
a new block(s), the result of the func
"""
import pandas.core.computation.expressions as expressions
assert errors in ['raise', 'ignore']
values = self.values
orig_other = other
if transpose:
values = values.T
other = getattr(other, '_values', getattr(other, 'values', other))
cond = getattr(cond, 'values', cond)
# If the default broadcasting would go in the wrong direction, then
# explicitly reshape other instead
if getattr(other, 'ndim', 0) >= 1:
if values.ndim - 1 == other.ndim and axis == 1:
other = other.reshape(tuple(other.shape + (1, )))
elif transpose and values.ndim == self.ndim - 1:
cond = cond.T
if not hasattr(cond, 'shape'):
raise ValueError("where must have a condition that is ndarray "
"like")
# our where function
def func(cond, values, other):
if cond.ravel().all():
return values
values, other = self._try_coerce_args(values, other)
try:
return self._try_coerce_result(expressions.where(
cond, values, other))
except Exception as detail:
if errors == 'raise':
raise TypeError(
'Could not operate [{other!r}] with block values '
'[{detail!s}]'.format(other=other, detail=detail))
else:
# return the values
result = np.empty(values.shape, dtype='float64')
result.fill(np.nan)
return result
# see if we can operate on the entire block, or need item-by-item
# or if we are a single block (ndim == 1)
try:
result = func(cond, values, other)
except TypeError:
# we cannot coerce, return a compat dtype
# we are explicitly ignoring errors
block = self.coerce_to_target_dtype(other)
blocks = block.where(orig_other, cond, align=align,
errors=errors,
try_cast=try_cast, axis=axis,
transpose=transpose)
return self._maybe_downcast(blocks, 'infer')
if self._can_hold_na or self.ndim == 1:
if transpose:
result = result.T
# try to cast if requested
if try_cast:
result = self._try_cast_result(result)
return self.make_block(result)
# might need to separate out blocks
axis = cond.ndim - 1
cond = cond.swapaxes(axis, 0)
mask = np.array([cond[i].all() for i in range(cond.shape[0])],
dtype=bool)
result_blocks = []
for m in [mask, ~mask]:
if m.any():
r = self._try_cast_result(result.take(m.nonzero()[0],
axis=axis))
result_blocks.append(
self.make_block(r.T, placement=self.mgr_locs[m]))
return result_blocks |
Return a list of unstacked blocks of self | def _unstack(self, unstacker_func, new_columns, n_rows, fill_value):
"""Return a list of unstacked blocks of self
Parameters
----------
unstacker_func : callable
Partially applied unstacker.
new_columns : Index
All columns of the unstacked BlockManager.
n_rows : int
Only used in ExtensionBlock.unstack
fill_value : int
Only used in ExtensionBlock.unstack
Returns
-------
blocks : list of Block
New blocks of unstacked values.
mask : array_like of bool
The mask of columns of `blocks` we should keep.
"""
unstacker = unstacker_func(self.values.T)
new_items = unstacker.get_new_columns()
new_placement = new_columns.get_indexer(new_items)
new_values, mask = unstacker.get_new_values()
mask = mask.any(0)
new_values = new_values.T[mask]
new_placement = new_placement[mask]
blocks = [make_block(new_values, placement=new_placement)]
return blocks, mask |
compute the quantiles of the | def quantile(self, qs, interpolation='linear', axis=0):
"""
compute the quantiles of the
Parameters
----------
qs: a scalar or list of the quantiles to be computed
interpolation: type of interpolation, default 'linear'
axis: axis to compute, default 0
Returns
-------
Block
"""
if self.is_datetimetz:
# TODO: cleanup this special case.
# We need to operate on i8 values for datetimetz
# but `Block.get_values()` returns an ndarray of objects
# right now. We need an API for "values to do numeric-like ops on"
values = self.values.asi8
# TODO: NonConsolidatableMixin shape
# Usual shape inconsistencies for ExtensionBlocks
if self.ndim > 1:
values = values[None, :]
else:
values = self.get_values()
values, _ = self._try_coerce_args(values, values)
is_empty = values.shape[axis] == 0
orig_scalar = not is_list_like(qs)
if orig_scalar:
# make list-like, unpack later
qs = [qs]
if is_empty:
if self.ndim == 1:
result = self._na_value
else:
# create the array of na_values
# 2d len(values) * len(qs)
result = np.repeat(np.array([self.fill_value] * len(qs)),
len(values)).reshape(len(values),
len(qs))
else:
# asarray needed for Sparse, see GH#24600
# TODO: Why self.values and not values?
mask = np.asarray(isna(self.values))
result = nanpercentile(values, np.array(qs) * 100,
axis=axis, na_value=self.fill_value,
mask=mask, ndim=self.ndim,
interpolation=interpolation)
result = np.array(result, copy=False)
if self.ndim > 1:
result = result.T
if orig_scalar and not lib.is_scalar(result):
# result could be scalar in case with is_empty and self.ndim == 1
assert result.shape[-1] == 1, result.shape
result = result[..., 0]
result = lib.item_from_zerodim(result)
ndim = getattr(result, 'ndim', None) or 0
result = self._try_coerce_result(result)
return make_block(result,
placement=np.arange(len(result)),
ndim=ndim) |
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