INSTRUCTION stringlengths 1 8.43k | RESPONSE stringlengths 75 104k |
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Return Python estimator estimatorParamMaps and evaluator from a Java ValidatorParams. | def _from_java_impl(cls, java_stage):
"""
Return Python estimator, estimatorParamMaps, and evaluator from a Java ValidatorParams.
"""
# Load information from java_stage to the instance.
estimator = JavaParams._from_java(java_stage.getEstimator())
evaluator = JavaParams._from_java(java_stage.getEvaluator())
epms = [estimator._transfer_param_map_from_java(epm)
for epm in java_stage.getEstimatorParamMaps()]
return estimator, epms, evaluator |
Return Java estimator estimatorParamMaps and evaluator from this Python instance. | def _to_java_impl(self):
"""
Return Java estimator, estimatorParamMaps, and evaluator from this Python instance.
"""
gateway = SparkContext._gateway
cls = SparkContext._jvm.org.apache.spark.ml.param.ParamMap
java_epms = gateway.new_array(cls, len(self.getEstimatorParamMaps()))
for idx, epm in enumerate(self.getEstimatorParamMaps()):
java_epms[idx] = self.getEstimator()._transfer_param_map_to_java(epm)
java_estimator = self.getEstimator()._to_java()
java_evaluator = self.getEvaluator()._to_java()
return java_estimator, java_epms, java_evaluator |
Given a Java CrossValidator create and return a Python wrapper of it. Used for ML persistence. | def _from_java(cls, java_stage):
"""
Given a Java CrossValidator, create and return a Python wrapper of it.
Used for ML persistence.
"""
estimator, epms, evaluator = super(CrossValidator, cls)._from_java_impl(java_stage)
numFolds = java_stage.getNumFolds()
seed = java_stage.getSeed()
parallelism = java_stage.getParallelism()
collectSubModels = java_stage.getCollectSubModels()
# Create a new instance of this stage.
py_stage = cls(estimator=estimator, estimatorParamMaps=epms, evaluator=evaluator,
numFolds=numFolds, seed=seed, parallelism=parallelism,
collectSubModels=collectSubModels)
py_stage._resetUid(java_stage.uid())
return py_stage |
Transfer this instance to a Java CrossValidator. Used for ML persistence. | def _to_java(self):
"""
Transfer this instance to a Java CrossValidator. Used for ML persistence.
:return: Java object equivalent to this instance.
"""
estimator, epms, evaluator = super(CrossValidator, self)._to_java_impl()
_java_obj = JavaParams._new_java_obj("org.apache.spark.ml.tuning.CrossValidator", self.uid)
_java_obj.setEstimatorParamMaps(epms)
_java_obj.setEvaluator(evaluator)
_java_obj.setEstimator(estimator)
_java_obj.setSeed(self.getSeed())
_java_obj.setNumFolds(self.getNumFolds())
_java_obj.setParallelism(self.getParallelism())
_java_obj.setCollectSubModels(self.getCollectSubModels())
return _java_obj |
Creates a copy of this instance with a randomly generated uid and some extra params. This copies the underlying bestModel creates a deep copy of the embedded paramMap and copies the embedded and extra parameters over. It does not copy the extra Params into the subModels. | def copy(self, extra=None):
"""
Creates a copy of this instance with a randomly generated uid
and some extra params. This copies the underlying bestModel,
creates a deep copy of the embedded paramMap, and
copies the embedded and extra parameters over.
It does not copy the extra Params into the subModels.
:param extra: Extra parameters to copy to the new instance
:return: Copy of this instance
"""
if extra is None:
extra = dict()
bestModel = self.bestModel.copy(extra)
avgMetrics = self.avgMetrics
subModels = self.subModels
return CrossValidatorModel(bestModel, avgMetrics, subModels) |
setParams ( self estimator = None estimatorParamMaps = None evaluator = None trainRatio = 0. 75 \ parallelism = 1 collectSubModels = False seed = None ): Sets params for the train validation split. | def setParams(self, estimator=None, estimatorParamMaps=None, evaluator=None, trainRatio=0.75,
parallelism=1, collectSubModels=False, seed=None):
"""
setParams(self, estimator=None, estimatorParamMaps=None, evaluator=None, trainRatio=0.75,\
parallelism=1, collectSubModels=False, seed=None):
Sets params for the train validation split.
"""
kwargs = self._input_kwargs
return self._set(**kwargs) |
Creates a copy of this instance with a randomly generated uid and some extra params. This copies creates a deep copy of the embedded paramMap and copies the embedded and extra parameters over. | def copy(self, extra=None):
"""
Creates a copy of this instance with a randomly generated uid
and some extra params. This copies creates a deep copy of
the embedded paramMap, and copies the embedded and extra parameters over.
:param extra: Extra parameters to copy to the new instance
:return: Copy of this instance
"""
if extra is None:
extra = dict()
newTVS = Params.copy(self, extra)
if self.isSet(self.estimator):
newTVS.setEstimator(self.getEstimator().copy(extra))
# estimatorParamMaps remain the same
if self.isSet(self.evaluator):
newTVS.setEvaluator(self.getEvaluator().copy(extra))
return newTVS |
Given a Java TrainValidationSplit create and return a Python wrapper of it. Used for ML persistence. | def _from_java(cls, java_stage):
"""
Given a Java TrainValidationSplit, create and return a Python wrapper of it.
Used for ML persistence.
"""
estimator, epms, evaluator = super(TrainValidationSplit, cls)._from_java_impl(java_stage)
trainRatio = java_stage.getTrainRatio()
seed = java_stage.getSeed()
parallelism = java_stage.getParallelism()
collectSubModels = java_stage.getCollectSubModels()
# Create a new instance of this stage.
py_stage = cls(estimator=estimator, estimatorParamMaps=epms, evaluator=evaluator,
trainRatio=trainRatio, seed=seed, parallelism=parallelism,
collectSubModels=collectSubModels)
py_stage._resetUid(java_stage.uid())
return py_stage |
Transfer this instance to a Java TrainValidationSplit. Used for ML persistence.: return: Java object equivalent to this instance. | def _to_java(self):
"""
Transfer this instance to a Java TrainValidationSplit. Used for ML persistence.
:return: Java object equivalent to this instance.
"""
estimator, epms, evaluator = super(TrainValidationSplit, self)._to_java_impl()
_java_obj = JavaParams._new_java_obj("org.apache.spark.ml.tuning.TrainValidationSplit",
self.uid)
_java_obj.setEstimatorParamMaps(epms)
_java_obj.setEvaluator(evaluator)
_java_obj.setEstimator(estimator)
_java_obj.setTrainRatio(self.getTrainRatio())
_java_obj.setSeed(self.getSeed())
_java_obj.setParallelism(self.getParallelism())
_java_obj.setCollectSubModels(self.getCollectSubModels())
return _java_obj |
Creates a copy of this instance with a randomly generated uid and some extra params. This copies the underlying bestModel creates a deep copy of the embedded paramMap and copies the embedded and extra parameters over. And this creates a shallow copy of the validationMetrics. It does not copy the extra Params into the subModels. | def copy(self, extra=None):
"""
Creates a copy of this instance with a randomly generated uid
and some extra params. This copies the underlying bestModel,
creates a deep copy of the embedded paramMap, and
copies the embedded and extra parameters over.
And, this creates a shallow copy of the validationMetrics.
It does not copy the extra Params into the subModels.
:param extra: Extra parameters to copy to the new instance
:return: Copy of this instance
"""
if extra is None:
extra = dict()
bestModel = self.bestModel.copy(extra)
validationMetrics = list(self.validationMetrics)
subModels = self.subModels
return TrainValidationSplitModel(bestModel, validationMetrics, subModels) |
Given a Java TrainValidationSplitModel create and return a Python wrapper of it. Used for ML persistence. | def _from_java(cls, java_stage):
"""
Given a Java TrainValidationSplitModel, create and return a Python wrapper of it.
Used for ML persistence.
"""
# Load information from java_stage to the instance.
bestModel = JavaParams._from_java(java_stage.bestModel())
estimator, epms, evaluator = super(TrainValidationSplitModel,
cls)._from_java_impl(java_stage)
# Create a new instance of this stage.
py_stage = cls(bestModel=bestModel).setEstimator(estimator)
py_stage = py_stage.setEstimatorParamMaps(epms).setEvaluator(evaluator)
if java_stage.hasSubModels():
py_stage.subModels = [JavaParams._from_java(sub_model)
for sub_model in java_stage.subModels()]
py_stage._resetUid(java_stage.uid())
return py_stage |
Transfer this instance to a Java TrainValidationSplitModel. Used for ML persistence.: return: Java object equivalent to this instance. | def _to_java(self):
"""
Transfer this instance to a Java TrainValidationSplitModel. Used for ML persistence.
:return: Java object equivalent to this instance.
"""
sc = SparkContext._active_spark_context
# TODO: persst validation metrics as well
_java_obj = JavaParams._new_java_obj(
"org.apache.spark.ml.tuning.TrainValidationSplitModel",
self.uid,
self.bestModel._to_java(),
_py2java(sc, []))
estimator, epms, evaluator = super(TrainValidationSplitModel, self)._to_java_impl()
_java_obj.set("evaluator", evaluator)
_java_obj.set("estimator", estimator)
_java_obj.set("estimatorParamMaps", epms)
if self.subModels is not None:
java_sub_models = [sub_model._to_java() for sub_model in self.subModels]
_java_obj.setSubModels(java_sub_models)
return _java_obj |
Returns the value of Spark runtime configuration property for the given key assuming it is set. | def get(self, key, default=_NoValue):
"""Returns the value of Spark runtime configuration property for the given key,
assuming it is set.
"""
self._checkType(key, "key")
if default is _NoValue:
return self._jconf.get(key)
else:
if default is not None:
self._checkType(default, "default")
return self._jconf.get(key, default) |
Assert that an object is of type str. | def _checkType(self, obj, identifier):
"""Assert that an object is of type str."""
if not isinstance(obj, basestring):
raise TypeError("expected %s '%s' to be a string (was '%s')" %
(identifier, obj, type(obj).__name__)) |
Create a PySpark function by its name | def _create_function(name, doc=""):
"""Create a PySpark function by its name"""
def _(col):
sc = SparkContext._active_spark_context
jc = getattr(sc._jvm.functions, name)(col._jc if isinstance(col, Column) else col)
return Column(jc)
_.__name__ = name
_.__doc__ = doc
return _ |
Similar with _create_function but creates a PySpark function that takes a column ( as string as well ). This is mainly for PySpark functions to take strings as column names. | def _create_function_over_column(name, doc=""):
"""Similar with `_create_function` but creates a PySpark function that takes a column
(as string as well). This is mainly for PySpark functions to take strings as
column names.
"""
def _(col):
sc = SparkContext._active_spark_context
jc = getattr(sc._jvm.functions, name)(_to_java_column(col))
return Column(jc)
_.__name__ = name
_.__doc__ = doc
return _ |
Wrap the deprecated function to print out deprecation warnings | def _wrap_deprecated_function(func, message):
""" Wrap the deprecated function to print out deprecation warnings"""
def _(col):
warnings.warn(message, DeprecationWarning)
return func(col)
return functools.wraps(func)(_) |
Create a binary mathfunction by name | def _create_binary_mathfunction(name, doc=""):
""" Create a binary mathfunction by name"""
def _(col1, col2):
sc = SparkContext._active_spark_context
# For legacy reasons, the arguments here can be implicitly converted into floats,
# if they are not columns or strings.
if isinstance(col1, Column):
arg1 = col1._jc
elif isinstance(col1, basestring):
arg1 = _create_column_from_name(col1)
else:
arg1 = float(col1)
if isinstance(col2, Column):
arg2 = col2._jc
elif isinstance(col2, basestring):
arg2 = _create_column_from_name(col2)
else:
arg2 = float(col2)
jc = getattr(sc._jvm.functions, name)(arg1, arg2)
return Column(jc)
_.__name__ = name
_.__doc__ = doc
return _ |
Create a window function by name | def _create_window_function(name, doc=''):
""" Create a window function by name """
def _():
sc = SparkContext._active_spark_context
jc = getattr(sc._jvm.functions, name)()
return Column(jc)
_.__name__ = name
_.__doc__ = 'Window function: ' + doc
return _ |
Aggregate function: returns a new: class: Column for approximate distinct count of column col. | def approx_count_distinct(col, rsd=None):
"""Aggregate function: returns a new :class:`Column` for approximate distinct count of
column `col`.
:param rsd: maximum estimation error allowed (default = 0.05). For rsd < 0.01, it is more
efficient to use :func:`countDistinct`
>>> df.agg(approx_count_distinct(df.age).alias('distinct_ages')).collect()
[Row(distinct_ages=2)]
"""
sc = SparkContext._active_spark_context
if rsd is None:
jc = sc._jvm.functions.approx_count_distinct(_to_java_column(col))
else:
jc = sc._jvm.functions.approx_count_distinct(_to_java_column(col), rsd)
return Column(jc) |
Marks a DataFrame as small enough for use in broadcast joins. | def broadcast(df):
"""Marks a DataFrame as small enough for use in broadcast joins."""
sc = SparkContext._active_spark_context
return DataFrame(sc._jvm.functions.broadcast(df._jdf), df.sql_ctx) |
Returns a new: class: Column for distinct count of col or cols. | def countDistinct(col, *cols):
"""Returns a new :class:`Column` for distinct count of ``col`` or ``cols``.
>>> df.agg(countDistinct(df.age, df.name).alias('c')).collect()
[Row(c=2)]
>>> df.agg(countDistinct("age", "name").alias('c')).collect()
[Row(c=2)]
"""
sc = SparkContext._active_spark_context
jc = sc._jvm.functions.countDistinct(_to_java_column(col), _to_seq(sc, cols, _to_java_column))
return Column(jc) |
Aggregate function: returns the last value in a group. | def last(col, ignorenulls=False):
"""Aggregate function: returns the last value in a group.
The function by default returns the last values it sees. It will return the last non-null
value it sees when ignoreNulls is set to true. If all values are null, then null is returned.
.. note:: The function is non-deterministic because its results depends on order of rows
which may be non-deterministic after a shuffle.
"""
sc = SparkContext._active_spark_context
jc = sc._jvm.functions.last(_to_java_column(col), ignorenulls)
return Column(jc) |
Returns col1 if it is not NaN or col2 if col1 is NaN. | def nanvl(col1, col2):
"""Returns col1 if it is not NaN, or col2 if col1 is NaN.
Both inputs should be floating point columns (:class:`DoubleType` or :class:`FloatType`).
>>> df = spark.createDataFrame([(1.0, float('nan')), (float('nan'), 2.0)], ("a", "b"))
>>> df.select(nanvl("a", "b").alias("r1"), nanvl(df.a, df.b).alias("r2")).collect()
[Row(r1=1.0, r2=1.0), Row(r1=2.0, r2=2.0)]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.nanvl(_to_java_column(col1), _to_java_column(col2))) |
Generates a random column with independent and identically distributed ( i. i. d. ) samples from U [ 0. 0 1. 0 ]. | def rand(seed=None):
"""Generates a random column with independent and identically distributed (i.i.d.) samples
from U[0.0, 1.0].
.. note:: The function is non-deterministic in general case.
>>> df.withColumn('rand', rand(seed=42) * 3).collect()
[Row(age=2, name=u'Alice', rand=2.4052597283576684),
Row(age=5, name=u'Bob', rand=2.3913904055683974)]
"""
sc = SparkContext._active_spark_context
if seed is not None:
jc = sc._jvm.functions.rand(seed)
else:
jc = sc._jvm.functions.rand()
return Column(jc) |
Round the given value to scale decimal places using HALF_UP rounding mode if scale > = 0 or at integral part when scale < 0. | def round(col, scale=0):
"""
Round the given value to `scale` decimal places using HALF_UP rounding mode if `scale` >= 0
or at integral part when `scale` < 0.
>>> spark.createDataFrame([(2.5,)], ['a']).select(round('a', 0).alias('r')).collect()
[Row(r=3.0)]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.round(_to_java_column(col), scale)) |
Shift the given value numBits left. | def shiftLeft(col, numBits):
"""Shift the given value numBits left.
>>> spark.createDataFrame([(21,)], ['a']).select(shiftLeft('a', 1).alias('r')).collect()
[Row(r=42)]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.shiftLeft(_to_java_column(col), numBits)) |
( Signed ) shift the given value numBits right. | def shiftRight(col, numBits):
"""(Signed) shift the given value numBits right.
>>> spark.createDataFrame([(42,)], ['a']).select(shiftRight('a', 1).alias('r')).collect()
[Row(r=21)]
"""
sc = SparkContext._active_spark_context
jc = sc._jvm.functions.shiftRight(_to_java_column(col), numBits)
return Column(jc) |
Parses the expression string into the column that it represents | def expr(str):
"""Parses the expression string into the column that it represents
>>> df.select(expr("length(name)")).collect()
[Row(length(name)=5), Row(length(name)=3)]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.expr(str)) |
Evaluates a list of conditions and returns one of multiple possible result expressions. If: func: Column. otherwise is not invoked None is returned for unmatched conditions. | def when(condition, value):
"""Evaluates a list of conditions and returns one of multiple possible result expressions.
If :func:`Column.otherwise` is not invoked, None is returned for unmatched conditions.
:param condition: a boolean :class:`Column` expression.
:param value: a literal value, or a :class:`Column` expression.
>>> df.select(when(df['age'] == 2, 3).otherwise(4).alias("age")).collect()
[Row(age=3), Row(age=4)]
>>> df.select(when(df.age == 2, df.age + 1).alias("age")).collect()
[Row(age=3), Row(age=None)]
"""
sc = SparkContext._active_spark_context
if not isinstance(condition, Column):
raise TypeError("condition should be a Column")
v = value._jc if isinstance(value, Column) else value
jc = sc._jvm.functions.when(condition._jc, v)
return Column(jc) |
Returns the first argument - based logarithm of the second argument. | def log(arg1, arg2=None):
"""Returns the first argument-based logarithm of the second argument.
If there is only one argument, then this takes the natural logarithm of the argument.
>>> df.select(log(10.0, df.age).alias('ten')).rdd.map(lambda l: str(l.ten)[:7]).collect()
['0.30102', '0.69897']
>>> df.select(log(df.age).alias('e')).rdd.map(lambda l: str(l.e)[:7]).collect()
['0.69314', '1.60943']
"""
sc = SparkContext._active_spark_context
if arg2 is None:
jc = sc._jvm.functions.log(_to_java_column(arg1))
else:
jc = sc._jvm.functions.log(arg1, _to_java_column(arg2))
return Column(jc) |
Convert a number in a string column from one base to another. | def conv(col, fromBase, toBase):
"""
Convert a number in a string column from one base to another.
>>> df = spark.createDataFrame([("010101",)], ['n'])
>>> df.select(conv(df.n, 2, 16).alias('hex')).collect()
[Row(hex=u'15')]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.conv(_to_java_column(col), fromBase, toBase)) |
Window function: returns the value that is offset rows before the current row and defaultValue if there is less than offset rows before the current row. For example an offset of one will return the previous row at any given point in the window partition. | def lag(col, offset=1, default=None):
"""
Window function: returns the value that is `offset` rows before the current row, and
`defaultValue` if there is less than `offset` rows before the current row. For example,
an `offset` of one will return the previous row at any given point in the window partition.
This is equivalent to the LAG function in SQL.
:param col: name of column or expression
:param offset: number of row to extend
:param default: default value
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.lag(_to_java_column(col), offset, default)) |
Window function: returns the ntile group id ( from 1 to n inclusive ) in an ordered window partition. For example if n is 4 the first quarter of the rows will get value 1 the second quarter will get 2 the third quarter will get 3 and the last quarter will get 4. | def ntile(n):
"""
Window function: returns the ntile group id (from 1 to `n` inclusive)
in an ordered window partition. For example, if `n` is 4, the first
quarter of the rows will get value 1, the second quarter will get 2,
the third quarter will get 3, and the last quarter will get 4.
This is equivalent to the NTILE function in SQL.
:param n: an integer
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.ntile(int(n))) |
Converts a date/ timestamp/ string to a value of string in the format specified by the date format given by the second argument. | def date_format(date, format):
"""
Converts a date/timestamp/string to a value of string in the format specified by the date
format given by the second argument.
A pattern could be for instance `dd.MM.yyyy` and could return a string like '18.03.1993'. All
pattern letters of the Java class `java.time.format.DateTimeFormatter` can be used.
.. note:: Use when ever possible specialized functions like `year`. These benefit from a
specialized implementation.
>>> df = spark.createDataFrame([('2015-04-08',)], ['dt'])
>>> df.select(date_format('dt', 'MM/dd/yyy').alias('date')).collect()
[Row(date=u'04/08/2015')]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.date_format(_to_java_column(date), format)) |
Returns the date that is days days after start | def date_add(start, days):
"""
Returns the date that is `days` days after `start`
>>> df = spark.createDataFrame([('2015-04-08',)], ['dt'])
>>> df.select(date_add(df.dt, 1).alias('next_date')).collect()
[Row(next_date=datetime.date(2015, 4, 9))]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.date_add(_to_java_column(start), days)) |
Returns the number of days from start to end. | def datediff(end, start):
"""
Returns the number of days from `start` to `end`.
>>> df = spark.createDataFrame([('2015-04-08','2015-05-10')], ['d1', 'd2'])
>>> df.select(datediff(df.d2, df.d1).alias('diff')).collect()
[Row(diff=32)]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.datediff(_to_java_column(end), _to_java_column(start))) |
Returns the date that is months months after start | def add_months(start, months):
"""
Returns the date that is `months` months after `start`
>>> df = spark.createDataFrame([('2015-04-08',)], ['dt'])
>>> df.select(add_months(df.dt, 1).alias('next_month')).collect()
[Row(next_month=datetime.date(2015, 5, 8))]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.add_months(_to_java_column(start), months)) |
Returns number of months between dates date1 and date2. If date1 is later than date2 then the result is positive. If date1 and date2 are on the same day of month or both are the last day of month returns an integer ( time of day will be ignored ). The result is rounded off to 8 digits unless roundOff is set to False. | def months_between(date1, date2, roundOff=True):
"""
Returns number of months between dates date1 and date2.
If date1 is later than date2, then the result is positive.
If date1 and date2 are on the same day of month, or both are the last day of month,
returns an integer (time of day will be ignored).
The result is rounded off to 8 digits unless `roundOff` is set to `False`.
>>> df = spark.createDataFrame([('1997-02-28 10:30:00', '1996-10-30')], ['date1', 'date2'])
>>> df.select(months_between(df.date1, df.date2).alias('months')).collect()
[Row(months=3.94959677)]
>>> df.select(months_between(df.date1, df.date2, False).alias('months')).collect()
[Row(months=3.9495967741935485)]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.months_between(
_to_java_column(date1), _to_java_column(date2), roundOff)) |
Converts a: class: Column of: class: pyspark. sql. types. StringType or: class: pyspark. sql. types. TimestampType into: class: pyspark. sql. types. DateType using the optionally specified format. Specify formats according to DateTimeFormatter <https:// docs. oracle. com/ javase/ 8/ docs/ api/ java/ time/ format/ DateTimeFormatter. html > _. # noqa By default it follows casting rules to: class: pyspark. sql. types. DateType if the format is omitted ( equivalent to col. cast ( date ) ). | def to_date(col, format=None):
"""Converts a :class:`Column` of :class:`pyspark.sql.types.StringType` or
:class:`pyspark.sql.types.TimestampType` into :class:`pyspark.sql.types.DateType`
using the optionally specified format. Specify formats according to
`DateTimeFormatter <https://docs.oracle.com/javase/8/docs/api/java/time/format/DateTimeFormatter.html>`_. # noqa
By default, it follows casting rules to :class:`pyspark.sql.types.DateType` if the format
is omitted (equivalent to ``col.cast("date")``).
>>> df = spark.createDataFrame([('1997-02-28 10:30:00',)], ['t'])
>>> df.select(to_date(df.t).alias('date')).collect()
[Row(date=datetime.date(1997, 2, 28))]
>>> df = spark.createDataFrame([('1997-02-28 10:30:00',)], ['t'])
>>> df.select(to_date(df.t, 'yyyy-MM-dd HH:mm:ss').alias('date')).collect()
[Row(date=datetime.date(1997, 2, 28))]
"""
sc = SparkContext._active_spark_context
if format is None:
jc = sc._jvm.functions.to_date(_to_java_column(col))
else:
jc = sc._jvm.functions.to_date(_to_java_column(col), format)
return Column(jc) |
Returns timestamp truncated to the unit specified by the format. | def date_trunc(format, timestamp):
"""
Returns timestamp truncated to the unit specified by the format.
:param format: 'year', 'yyyy', 'yy', 'month', 'mon', 'mm',
'day', 'dd', 'hour', 'minute', 'second', 'week', 'quarter'
>>> df = spark.createDataFrame([('1997-02-28 05:02:11',)], ['t'])
>>> df.select(date_trunc('year', df.t).alias('year')).collect()
[Row(year=datetime.datetime(1997, 1, 1, 0, 0))]
>>> df.select(date_trunc('mon', df.t).alias('month')).collect()
[Row(month=datetime.datetime(1997, 2, 1, 0, 0))]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.date_trunc(format, _to_java_column(timestamp))) |
Returns the first date which is later than the value of the date column. | def next_day(date, dayOfWeek):
"""
Returns the first date which is later than the value of the date column.
Day of the week parameter is case insensitive, and accepts:
"Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun".
>>> df = spark.createDataFrame([('2015-07-27',)], ['d'])
>>> df.select(next_day(df.d, 'Sun').alias('date')).collect()
[Row(date=datetime.date(2015, 8, 2))]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.next_day(_to_java_column(date), dayOfWeek)) |
Returns the last day of the month which the given date belongs to. | def last_day(date):
"""
Returns the last day of the month which the given date belongs to.
>>> df = spark.createDataFrame([('1997-02-10',)], ['d'])
>>> df.select(last_day(df.d).alias('date')).collect()
[Row(date=datetime.date(1997, 2, 28))]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.last_day(_to_java_column(date))) |
Convert time string with given pattern ( yyyy - MM - dd HH: mm: ss by default ) to Unix time stamp ( in seconds ) using the default timezone and the default locale return null if fail. | def unix_timestamp(timestamp=None, format='yyyy-MM-dd HH:mm:ss'):
"""
Convert time string with given pattern ('yyyy-MM-dd HH:mm:ss', by default)
to Unix time stamp (in seconds), using the default timezone and the default
locale, return null if fail.
if `timestamp` is None, then it returns current timestamp.
>>> spark.conf.set("spark.sql.session.timeZone", "America/Los_Angeles")
>>> time_df = spark.createDataFrame([('2015-04-08',)], ['dt'])
>>> time_df.select(unix_timestamp('dt', 'yyyy-MM-dd').alias('unix_time')).collect()
[Row(unix_time=1428476400)]
>>> spark.conf.unset("spark.sql.session.timeZone")
"""
sc = SparkContext._active_spark_context
if timestamp is None:
return Column(sc._jvm.functions.unix_timestamp())
return Column(sc._jvm.functions.unix_timestamp(_to_java_column(timestamp), format)) |
This is a common function for databases supporting TIMESTAMP WITHOUT TIMEZONE. This function takes a timestamp which is timezone - agnostic and interprets it as a timestamp in UTC and renders that timestamp as a timestamp in the given time zone. | def from_utc_timestamp(timestamp, tz):
"""
This is a common function for databases supporting TIMESTAMP WITHOUT TIMEZONE. This function
takes a timestamp which is timezone-agnostic, and interprets it as a timestamp in UTC, and
renders that timestamp as a timestamp in the given time zone.
However, timestamp in Spark represents number of microseconds from the Unix epoch, which is not
timezone-agnostic. So in Spark this function just shift the timestamp value from UTC timezone to
the given timezone.
This function may return confusing result if the input is a string with timezone, e.g.
'2018-03-13T06:18:23+00:00'. The reason is that, Spark firstly cast the string to timestamp
according to the timezone in the string, and finally display the result by converting the
timestamp to string according to the session local timezone.
:param timestamp: the column that contains timestamps
:param tz: a string that has the ID of timezone, e.g. "GMT", "America/Los_Angeles", etc
.. versionchanged:: 2.4
`tz` can take a :class:`Column` containing timezone ID strings.
>>> df = spark.createDataFrame([('1997-02-28 10:30:00', 'JST')], ['ts', 'tz'])
>>> df.select(from_utc_timestamp(df.ts, "PST").alias('local_time')).collect()
[Row(local_time=datetime.datetime(1997, 2, 28, 2, 30))]
>>> df.select(from_utc_timestamp(df.ts, df.tz).alias('local_time')).collect()
[Row(local_time=datetime.datetime(1997, 2, 28, 19, 30))]
.. note:: Deprecated in 3.0. See SPARK-25496
"""
warnings.warn("Deprecated in 3.0. See SPARK-25496", DeprecationWarning)
sc = SparkContext._active_spark_context
if isinstance(tz, Column):
tz = _to_java_column(tz)
return Column(sc._jvm.functions.from_utc_timestamp(_to_java_column(timestamp), tz)) |
Bucketize rows into one or more time windows given a timestamp specifying column. Window starts are inclusive but the window ends are exclusive e. g. 12: 05 will be in the window [ 12: 05 12: 10 ) but not in [ 12: 00 12: 05 ). Windows can support microsecond precision. Windows in the order of months are not supported. | def window(timeColumn, windowDuration, slideDuration=None, startTime=None):
"""Bucketize rows into one or more time windows given a timestamp specifying column. Window
starts are inclusive but the window ends are exclusive, e.g. 12:05 will be in the window
[12:05,12:10) but not in [12:00,12:05). Windows can support microsecond precision. Windows in
the order of months are not supported.
The time column must be of :class:`pyspark.sql.types.TimestampType`.
Durations are provided as strings, e.g. '1 second', '1 day 12 hours', '2 minutes'. Valid
interval strings are 'week', 'day', 'hour', 'minute', 'second', 'millisecond', 'microsecond'.
If the ``slideDuration`` is not provided, the windows will be tumbling windows.
The startTime is the offset with respect to 1970-01-01 00:00:00 UTC with which to start
window intervals. For example, in order to have hourly tumbling windows that start 15 minutes
past the hour, e.g. 12:15-13:15, 13:15-14:15... provide `startTime` as `15 minutes`.
The output column will be a struct called 'window' by default with the nested columns 'start'
and 'end', where 'start' and 'end' will be of :class:`pyspark.sql.types.TimestampType`.
>>> df = spark.createDataFrame([("2016-03-11 09:00:07", 1)]).toDF("date", "val")
>>> w = df.groupBy(window("date", "5 seconds")).agg(sum("val").alias("sum"))
>>> w.select(w.window.start.cast("string").alias("start"),
... w.window.end.cast("string").alias("end"), "sum").collect()
[Row(start=u'2016-03-11 09:00:05', end=u'2016-03-11 09:00:10', sum=1)]
"""
def check_string_field(field, fieldName):
if not field or type(field) is not str:
raise TypeError("%s should be provided as a string" % fieldName)
sc = SparkContext._active_spark_context
time_col = _to_java_column(timeColumn)
check_string_field(windowDuration, "windowDuration")
if slideDuration and startTime:
check_string_field(slideDuration, "slideDuration")
check_string_field(startTime, "startTime")
res = sc._jvm.functions.window(time_col, windowDuration, slideDuration, startTime)
elif slideDuration:
check_string_field(slideDuration, "slideDuration")
res = sc._jvm.functions.window(time_col, windowDuration, slideDuration)
elif startTime:
check_string_field(startTime, "startTime")
res = sc._jvm.functions.window(time_col, windowDuration, windowDuration, startTime)
else:
res = sc._jvm.functions.window(time_col, windowDuration)
return Column(res) |
Calculates the hash code of given columns and returns the result as an int column. | def hash(*cols):
"""Calculates the hash code of given columns, and returns the result as an int column.
>>> spark.createDataFrame([('ABC',)], ['a']).select(hash('a').alias('hash')).collect()
[Row(hash=-757602832)]
"""
sc = SparkContext._active_spark_context
jc = sc._jvm.functions.hash(_to_seq(sc, cols, _to_java_column))
return Column(jc) |
Concatenates multiple input string columns together into a single string column using the given separator. | def concat_ws(sep, *cols):
"""
Concatenates multiple input string columns together into a single string column,
using the given separator.
>>> df = spark.createDataFrame([('abcd','123')], ['s', 'd'])
>>> df.select(concat_ws('-', df.s, df.d).alias('s')).collect()
[Row(s=u'abcd-123')]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.concat_ws(sep, _to_seq(sc, cols, _to_java_column))) |
Computes the first argument into a string from a binary using the provided character set ( one of US - ASCII ISO - 8859 - 1 UTF - 8 UTF - 16BE UTF - 16LE UTF - 16 ). | def decode(col, charset):
"""
Computes the first argument into a string from a binary using the provided character set
(one of 'US-ASCII', 'ISO-8859-1', 'UTF-8', 'UTF-16BE', 'UTF-16LE', 'UTF-16').
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.decode(_to_java_column(col), charset)) |
Formats the number X to a format like # -- # -- #. -- rounded to d decimal places with HALF_EVEN round mode and returns the result as a string. | def format_number(col, d):
"""
Formats the number X to a format like '#,--#,--#.--', rounded to d decimal places
with HALF_EVEN round mode, and returns the result as a string.
:param col: the column name of the numeric value to be formatted
:param d: the N decimal places
>>> spark.createDataFrame([(5,)], ['a']).select(format_number('a', 4).alias('v')).collect()
[Row(v=u'5.0000')]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.format_number(_to_java_column(col), d)) |
Formats the arguments in printf - style and returns the result as a string column. | def format_string(format, *cols):
"""
Formats the arguments in printf-style and returns the result as a string column.
:param col: the column name of the numeric value to be formatted
:param d: the N decimal places
>>> df = spark.createDataFrame([(5, "hello")], ['a', 'b'])
>>> df.select(format_string('%d %s', df.a, df.b).alias('v')).collect()
[Row(v=u'5 hello')]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.format_string(format, _to_seq(sc, cols, _to_java_column))) |
Locate the position of the first occurrence of substr column in the given string. Returns null if either of the arguments are null. | def instr(str, substr):
"""
Locate the position of the first occurrence of substr column in the given string.
Returns null if either of the arguments are null.
.. note:: The position is not zero based, but 1 based index. Returns 0 if substr
could not be found in str.
>>> df = spark.createDataFrame([('abcd',)], ['s',])
>>> df.select(instr(df.s, 'b').alias('s')).collect()
[Row(s=2)]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.instr(_to_java_column(str), substr)) |
Substring starts at pos and is of length len when str is String type or returns the slice of byte array that starts at pos in byte and is of length len when str is Binary type. | def substring(str, pos, len):
"""
Substring starts at `pos` and is of length `len` when str is String type or
returns the slice of byte array that starts at `pos` in byte and is of length `len`
when str is Binary type.
.. note:: The position is not zero based, but 1 based index.
>>> df = spark.createDataFrame([('abcd',)], ['s',])
>>> df.select(substring(df.s, 1, 2).alias('s')).collect()
[Row(s=u'ab')]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.substring(_to_java_column(str), pos, len)) |
Returns the substring from string str before count occurrences of the delimiter delim. If count is positive everything the left of the final delimiter ( counting from left ) is returned. If count is negative every to the right of the final delimiter ( counting from the right ) is returned. substring_index performs a case - sensitive match when searching for delim. | def substring_index(str, delim, count):
"""
Returns the substring from string str before count occurrences of the delimiter delim.
If count is positive, everything the left of the final delimiter (counting from left) is
returned. If count is negative, every to the right of the final delimiter (counting from the
right) is returned. substring_index performs a case-sensitive match when searching for delim.
>>> df = spark.createDataFrame([('a.b.c.d',)], ['s'])
>>> df.select(substring_index(df.s, '.', 2).alias('s')).collect()
[Row(s=u'a.b')]
>>> df.select(substring_index(df.s, '.', -3).alias('s')).collect()
[Row(s=u'b.c.d')]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.substring_index(_to_java_column(str), delim, count)) |
Computes the Levenshtein distance of the two given strings. | def levenshtein(left, right):
"""Computes the Levenshtein distance of the two given strings.
>>> df0 = spark.createDataFrame([('kitten', 'sitting',)], ['l', 'r'])
>>> df0.select(levenshtein('l', 'r').alias('d')).collect()
[Row(d=3)]
"""
sc = SparkContext._active_spark_context
jc = sc._jvm.functions.levenshtein(_to_java_column(left), _to_java_column(right))
return Column(jc) |
Locate the position of the first occurrence of substr in a string column after position pos. | def locate(substr, str, pos=1):
"""
Locate the position of the first occurrence of substr in a string column, after position pos.
.. note:: The position is not zero based, but 1 based index. Returns 0 if substr
could not be found in str.
:param substr: a string
:param str: a Column of :class:`pyspark.sql.types.StringType`
:param pos: start position (zero based)
>>> df = spark.createDataFrame([('abcd',)], ['s',])
>>> df.select(locate('b', df.s, 1).alias('s')).collect()
[Row(s=2)]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.locate(substr, _to_java_column(str), pos)) |
Left - pad the string column to width len with pad. | def lpad(col, len, pad):
"""
Left-pad the string column to width `len` with `pad`.
>>> df = spark.createDataFrame([('abcd',)], ['s',])
>>> df.select(lpad(df.s, 6, '#').alias('s')).collect()
[Row(s=u'##abcd')]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.lpad(_to_java_column(col), len, pad)) |
Repeats a string column n times and returns it as a new string column. | def repeat(col, n):
"""
Repeats a string column n times, and returns it as a new string column.
>>> df = spark.createDataFrame([('ab',)], ['s',])
>>> df.select(repeat(df.s, 3).alias('s')).collect()
[Row(s=u'ababab')]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.repeat(_to_java_column(col), n)) |
Splits str around matches of the given pattern. | def split(str, pattern, limit=-1):
"""
Splits str around matches of the given pattern.
:param str: a string expression to split
:param pattern: a string representing a regular expression. The regex string should be
a Java regular expression.
:param limit: an integer which controls the number of times `pattern` is applied.
* ``limit > 0``: The resulting array's length will not be more than `limit`, and the
resulting array's last entry will contain all input beyond the last
matched pattern.
* ``limit <= 0``: `pattern` will be applied as many times as possible, and the resulting
array can be of any size.
.. versionchanged:: 3.0
`split` now takes an optional `limit` field. If not provided, default limit value is -1.
>>> df = spark.createDataFrame([('oneAtwoBthreeC',)], ['s',])
>>> df.select(split(df.s, '[ABC]', 2).alias('s')).collect()
[Row(s=[u'one', u'twoBthreeC'])]
>>> df.select(split(df.s, '[ABC]', -1).alias('s')).collect()
[Row(s=[u'one', u'two', u'three', u''])]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.split(_to_java_column(str), pattern, limit)) |
r Extract a specific group matched by a Java regex from the specified string column. If the regex did not match or the specified group did not match an empty string is returned. | def regexp_extract(str, pattern, idx):
r"""Extract a specific group matched by a Java regex, from the specified string column.
If the regex did not match, or the specified group did not match, an empty string is returned.
>>> df = spark.createDataFrame([('100-200',)], ['str'])
>>> df.select(regexp_extract('str', r'(\d+)-(\d+)', 1).alias('d')).collect()
[Row(d=u'100')]
>>> df = spark.createDataFrame([('foo',)], ['str'])
>>> df.select(regexp_extract('str', r'(\d+)', 1).alias('d')).collect()
[Row(d=u'')]
>>> df = spark.createDataFrame([('aaaac',)], ['str'])
>>> df.select(regexp_extract('str', '(a+)(b)?(c)', 2).alias('d')).collect()
[Row(d=u'')]
"""
sc = SparkContext._active_spark_context
jc = sc._jvm.functions.regexp_extract(_to_java_column(str), pattern, idx)
return Column(jc) |
r Replace all substrings of the specified string value that match regexp with rep. | def regexp_replace(str, pattern, replacement):
r"""Replace all substrings of the specified string value that match regexp with rep.
>>> df = spark.createDataFrame([('100-200',)], ['str'])
>>> df.select(regexp_replace('str', r'(\d+)', '--').alias('d')).collect()
[Row(d=u'-----')]
"""
sc = SparkContext._active_spark_context
jc = sc._jvm.functions.regexp_replace(_to_java_column(str), pattern, replacement)
return Column(jc) |
A function translate any character in the srcCol by a character in matching. The characters in replace is corresponding to the characters in matching. The translate will happen when any character in the string matching with the character in the matching. | def translate(srcCol, matching, replace):
"""A function translate any character in the `srcCol` by a character in `matching`.
The characters in `replace` is corresponding to the characters in `matching`.
The translate will happen when any character in the string matching with the character
in the `matching`.
>>> spark.createDataFrame([('translate',)], ['a']).select(translate('a', "rnlt", "123") \\
... .alias('r')).collect()
[Row(r=u'1a2s3ae')]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.translate(_to_java_column(srcCol), matching, replace)) |
Collection function: returns true if the arrays contain any common non - null element ; if not returns null if both the arrays are non - empty and any of them contains a null element ; returns false otherwise. | def arrays_overlap(a1, a2):
"""
Collection function: returns true if the arrays contain any common non-null element; if not,
returns null if both the arrays are non-empty and any of them contains a null element; returns
false otherwise.
>>> df = spark.createDataFrame([(["a", "b"], ["b", "c"]), (["a"], ["b", "c"])], ['x', 'y'])
>>> df.select(arrays_overlap(df.x, df.y).alias("overlap")).collect()
[Row(overlap=True), Row(overlap=False)]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.arrays_overlap(_to_java_column(a1), _to_java_column(a2))) |
Collection function: returns an array containing all the elements in x from index start ( or starting from the end if start is negative ) with the specified length. >>> df = spark. createDataFrame ( [ ( [ 1 2 3 ] ) ( [ 4 5 ] ) ] [ x ] ) >>> df. select ( slice ( df. x 2 2 ). alias ( sliced )). collect () [ Row ( sliced = [ 2 3 ] ) Row ( sliced = [ 5 ] ) ] | def slice(x, start, length):
"""
Collection function: returns an array containing all the elements in `x` from index `start`
(or starting from the end if `start` is negative) with the specified `length`.
>>> df = spark.createDataFrame([([1, 2, 3],), ([4, 5],)], ['x'])
>>> df.select(slice(df.x, 2, 2).alias("sliced")).collect()
[Row(sliced=[2, 3]), Row(sliced=[5])]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.slice(_to_java_column(x), start, length)) |
Concatenates the elements of column using the delimiter. Null values are replaced with null_replacement if set otherwise they are ignored. | def array_join(col, delimiter, null_replacement=None):
"""
Concatenates the elements of `column` using the `delimiter`. Null values are replaced with
`null_replacement` if set, otherwise they are ignored.
>>> df = spark.createDataFrame([(["a", "b", "c"],), (["a", None],)], ['data'])
>>> df.select(array_join(df.data, ",").alias("joined")).collect()
[Row(joined=u'a,b,c'), Row(joined=u'a')]
>>> df.select(array_join(df.data, ",", "NULL").alias("joined")).collect()
[Row(joined=u'a,b,c'), Row(joined=u'a,NULL')]
"""
sc = SparkContext._active_spark_context
if null_replacement is None:
return Column(sc._jvm.functions.array_join(_to_java_column(col), delimiter))
else:
return Column(sc._jvm.functions.array_join(
_to_java_column(col), delimiter, null_replacement)) |
Concatenates multiple input columns together into a single column. The function works with strings binary and compatible array columns. | def concat(*cols):
"""
Concatenates multiple input columns together into a single column.
The function works with strings, binary and compatible array columns.
>>> df = spark.createDataFrame([('abcd','123')], ['s', 'd'])
>>> df.select(concat(df.s, df.d).alias('s')).collect()
[Row(s=u'abcd123')]
>>> df = spark.createDataFrame([([1, 2], [3, 4], [5]), ([1, 2], None, [3])], ['a', 'b', 'c'])
>>> df.select(concat(df.a, df.b, df.c).alias("arr")).collect()
[Row(arr=[1, 2, 3, 4, 5]), Row(arr=None)]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.concat(_to_seq(sc, cols, _to_java_column))) |
Collection function: Locates the position of the first occurrence of the given value in the given array. Returns null if either of the arguments are null. | def array_position(col, value):
"""
Collection function: Locates the position of the first occurrence of the given value
in the given array. Returns null if either of the arguments are null.
.. note:: The position is not zero based, but 1 based index. Returns 0 if the given
value could not be found in the array.
>>> df = spark.createDataFrame([(["c", "b", "a"],), ([],)], ['data'])
>>> df.select(array_position(df.data, "a")).collect()
[Row(array_position(data, a)=3), Row(array_position(data, a)=0)]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.array_position(_to_java_column(col), value)) |
Collection function: Returns element of array at given index in extraction if col is array. Returns value for the given key in extraction if col is map. | def element_at(col, extraction):
"""
Collection function: Returns element of array at given index in extraction if col is array.
Returns value for the given key in extraction if col is map.
:param col: name of column containing array or map
:param extraction: index to check for in array or key to check for in map
.. note:: The position is not zero based, but 1 based index.
>>> df = spark.createDataFrame([(["a", "b", "c"],), ([],)], ['data'])
>>> df.select(element_at(df.data, 1)).collect()
[Row(element_at(data, 1)=u'a'), Row(element_at(data, 1)=None)]
>>> df = spark.createDataFrame([({"a": 1.0, "b": 2.0},), ({},)], ['data'])
>>> df.select(element_at(df.data, "a")).collect()
[Row(element_at(data, a)=1.0), Row(element_at(data, a)=None)]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.element_at(_to_java_column(col), extraction)) |
Collection function: Remove all elements that equal to element from the given array. | def array_remove(col, element):
"""
Collection function: Remove all elements that equal to element from the given array.
:param col: name of column containing array
:param element: element to be removed from the array
>>> df = spark.createDataFrame([([1, 2, 3, 1, 1],), ([],)], ['data'])
>>> df.select(array_remove(df.data, 1)).collect()
[Row(array_remove(data, 1)=[2, 3]), Row(array_remove(data, 1)=[])]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.array_remove(_to_java_column(col), element)) |
Returns a new row for each element in the given array or map. Uses the default column name col for elements in the array and key and value for elements in the map unless specified otherwise. | def explode(col):
"""
Returns a new row for each element in the given array or map.
Uses the default column name `col` for elements in the array and
`key` and `value` for elements in the map unless specified otherwise.
>>> from pyspark.sql import Row
>>> eDF = spark.createDataFrame([Row(a=1, intlist=[1,2,3], mapfield={"a": "b"})])
>>> eDF.select(explode(eDF.intlist).alias("anInt")).collect()
[Row(anInt=1), Row(anInt=2), Row(anInt=3)]
>>> eDF.select(explode(eDF.mapfield).alias("key", "value")).show()
+---+-----+
|key|value|
+---+-----+
| a| b|
+---+-----+
"""
sc = SparkContext._active_spark_context
jc = sc._jvm.functions.explode(_to_java_column(col))
return Column(jc) |
Extracts json object from a json string based on json path specified and returns json string of the extracted json object. It will return null if the input json string is invalid. | def get_json_object(col, path):
"""
Extracts json object from a json string based on json path specified, and returns json string
of the extracted json object. It will return null if the input json string is invalid.
:param col: string column in json format
:param path: path to the json object to extract
>>> data = [("1", '''{"f1": "value1", "f2": "value2"}'''), ("2", '''{"f1": "value12"}''')]
>>> df = spark.createDataFrame(data, ("key", "jstring"))
>>> df.select(df.key, get_json_object(df.jstring, '$.f1').alias("c0"), \\
... get_json_object(df.jstring, '$.f2').alias("c1") ).collect()
[Row(key=u'1', c0=u'value1', c1=u'value2'), Row(key=u'2', c0=u'value12', c1=None)]
"""
sc = SparkContext._active_spark_context
jc = sc._jvm.functions.get_json_object(_to_java_column(col), path)
return Column(jc) |
Creates a new row for a json column according to the given field names. | def json_tuple(col, *fields):
"""Creates a new row for a json column according to the given field names.
:param col: string column in json format
:param fields: list of fields to extract
>>> data = [("1", '''{"f1": "value1", "f2": "value2"}'''), ("2", '''{"f1": "value12"}''')]
>>> df = spark.createDataFrame(data, ("key", "jstring"))
>>> df.select(df.key, json_tuple(df.jstring, 'f1', 'f2')).collect()
[Row(key=u'1', c0=u'value1', c1=u'value2'), Row(key=u'2', c0=u'value12', c1=None)]
"""
sc = SparkContext._active_spark_context
jc = sc._jvm.functions.json_tuple(_to_java_column(col), _to_seq(sc, fields))
return Column(jc) |
Parses a column containing a JSON string into a: class: MapType with: class: StringType as keys type: class: StructType or: class: ArrayType with the specified schema. Returns null in the case of an unparseable string. | def from_json(col, schema, options={}):
"""
Parses a column containing a JSON string into a :class:`MapType` with :class:`StringType`
as keys type, :class:`StructType` or :class:`ArrayType` with
the specified schema. Returns `null`, in the case of an unparseable string.
:param col: string column in json format
:param schema: a StructType or ArrayType of StructType to use when parsing the json column.
:param options: options to control parsing. accepts the same options as the json datasource
.. note:: Since Spark 2.3, the DDL-formatted string or a JSON format string is also
supported for ``schema``.
>>> from pyspark.sql.types import *
>>> data = [(1, '''{"a": 1}''')]
>>> schema = StructType([StructField("a", IntegerType())])
>>> df = spark.createDataFrame(data, ("key", "value"))
>>> df.select(from_json(df.value, schema).alias("json")).collect()
[Row(json=Row(a=1))]
>>> df.select(from_json(df.value, "a INT").alias("json")).collect()
[Row(json=Row(a=1))]
>>> df.select(from_json(df.value, "MAP<STRING,INT>").alias("json")).collect()
[Row(json={u'a': 1})]
>>> data = [(1, '''[{"a": 1}]''')]
>>> schema = ArrayType(StructType([StructField("a", IntegerType())]))
>>> df = spark.createDataFrame(data, ("key", "value"))
>>> df.select(from_json(df.value, schema).alias("json")).collect()
[Row(json=[Row(a=1)])]
>>> schema = schema_of_json(lit('''{"a": 0}'''))
>>> df.select(from_json(df.value, schema).alias("json")).collect()
[Row(json=Row(a=None))]
>>> data = [(1, '''[1, 2, 3]''')]
>>> schema = ArrayType(IntegerType())
>>> df = spark.createDataFrame(data, ("key", "value"))
>>> df.select(from_json(df.value, schema).alias("json")).collect()
[Row(json=[1, 2, 3])]
"""
sc = SparkContext._active_spark_context
if isinstance(schema, DataType):
schema = schema.json()
elif isinstance(schema, Column):
schema = _to_java_column(schema)
jc = sc._jvm.functions.from_json(_to_java_column(col), schema, options)
return Column(jc) |
Parses a JSON string and infers its schema in DDL format. | def schema_of_json(json, options={}):
"""
Parses a JSON string and infers its schema in DDL format.
:param json: a JSON string or a string literal containing a JSON string.
:param options: options to control parsing. accepts the same options as the JSON datasource
.. versionchanged:: 3.0
It accepts `options` parameter to control schema inferring.
>>> df = spark.range(1)
>>> df.select(schema_of_json(lit('{"a": 0}')).alias("json")).collect()
[Row(json=u'struct<a:bigint>')]
>>> schema = schema_of_json('{a: 1}', {'allowUnquotedFieldNames':'true'})
>>> df.select(schema.alias("json")).collect()
[Row(json=u'struct<a:bigint>')]
"""
if isinstance(json, basestring):
col = _create_column_from_literal(json)
elif isinstance(json, Column):
col = _to_java_column(json)
else:
raise TypeError("schema argument should be a column or string")
sc = SparkContext._active_spark_context
jc = sc._jvm.functions.schema_of_json(col, options)
return Column(jc) |
Parses a CSV string and infers its schema in DDL format. | def schema_of_csv(csv, options={}):
"""
Parses a CSV string and infers its schema in DDL format.
:param col: a CSV string or a string literal containing a CSV string.
:param options: options to control parsing. accepts the same options as the CSV datasource
>>> df = spark.range(1)
>>> df.select(schema_of_csv(lit('1|a'), {'sep':'|'}).alias("csv")).collect()
[Row(csv=u'struct<_c0:int,_c1:string>')]
>>> df.select(schema_of_csv('1|a', {'sep':'|'}).alias("csv")).collect()
[Row(csv=u'struct<_c0:int,_c1:string>')]
"""
if isinstance(csv, basestring):
col = _create_column_from_literal(csv)
elif isinstance(csv, Column):
col = _to_java_column(csv)
else:
raise TypeError("schema argument should be a column or string")
sc = SparkContext._active_spark_context
jc = sc._jvm.functions.schema_of_csv(col, options)
return Column(jc) |
Converts a column containing a: class: StructType into a CSV string. Throws an exception in the case of an unsupported type. | def to_csv(col, options={}):
"""
Converts a column containing a :class:`StructType` into a CSV string.
Throws an exception, in the case of an unsupported type.
:param col: name of column containing a struct.
:param options: options to control converting. accepts the same options as the CSV datasource.
>>> from pyspark.sql import Row
>>> data = [(1, Row(name='Alice', age=2))]
>>> df = spark.createDataFrame(data, ("key", "value"))
>>> df.select(to_csv(df.value).alias("csv")).collect()
[Row(csv=u'2,Alice')]
"""
sc = SparkContext._active_spark_context
jc = sc._jvm.functions.to_csv(_to_java_column(col), options)
return Column(jc) |
Collection function: returns the length of the array or map stored in the column. | def size(col):
"""
Collection function: returns the length of the array or map stored in the column.
:param col: name of column or expression
>>> df = spark.createDataFrame([([1, 2, 3],),([1],),([],)], ['data'])
>>> df.select(size(df.data)).collect()
[Row(size(data)=3), Row(size(data)=1), Row(size(data)=0)]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.size(_to_java_column(col))) |
Collection function: sorts the input array in ascending or descending order according to the natural ordering of the array elements. Null elements will be placed at the beginning of the returned array in ascending order or at the end of the returned array in descending order. | def sort_array(col, asc=True):
"""
Collection function: sorts the input array in ascending or descending order according
to the natural ordering of the array elements. Null elements will be placed at the beginning
of the returned array in ascending order or at the end of the returned array in descending
order.
:param col: name of column or expression
>>> df = spark.createDataFrame([([2, 1, None, 3],),([1],),([],)], ['data'])
>>> df.select(sort_array(df.data).alias('r')).collect()
[Row(r=[None, 1, 2, 3]), Row(r=[1]), Row(r=[])]
>>> df.select(sort_array(df.data, asc=False).alias('r')).collect()
[Row(r=[3, 2, 1, None]), Row(r=[1]), Row(r=[])]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.sort_array(_to_java_column(col), asc)) |
Collection function: creates an array containing a column repeated count times. | def array_repeat(col, count):
"""
Collection function: creates an array containing a column repeated count times.
>>> df = spark.createDataFrame([('ab',)], ['data'])
>>> df.select(array_repeat(df.data, 3).alias('r')).collect()
[Row(r=[u'ab', u'ab', u'ab'])]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.array_repeat(_to_java_column(col), count)) |
Returns the union of all the given maps. | def map_concat(*cols):
"""Returns the union of all the given maps.
:param cols: list of column names (string) or list of :class:`Column` expressions
>>> from pyspark.sql.functions import map_concat
>>> df = spark.sql("SELECT map(1, 'a', 2, 'b') as map1, map(3, 'c', 1, 'd') as map2")
>>> df.select(map_concat("map1", "map2").alias("map3")).show(truncate=False)
+------------------------+
|map3 |
+------------------------+
|[1 -> d, 2 -> b, 3 -> c]|
+------------------------+
"""
sc = SparkContext._active_spark_context
if len(cols) == 1 and isinstance(cols[0], (list, set)):
cols = cols[0]
jc = sc._jvm.functions.map_concat(_to_seq(sc, cols, _to_java_column))
return Column(jc) |
Generate a sequence of integers from start to stop incrementing by step. If step is not set incrementing by 1 if start is less than or equal to stop otherwise - 1. | def sequence(start, stop, step=None):
"""
Generate a sequence of integers from `start` to `stop`, incrementing by `step`.
If `step` is not set, incrementing by 1 if `start` is less than or equal to `stop`,
otherwise -1.
>>> df1 = spark.createDataFrame([(-2, 2)], ('C1', 'C2'))
>>> df1.select(sequence('C1', 'C2').alias('r')).collect()
[Row(r=[-2, -1, 0, 1, 2])]
>>> df2 = spark.createDataFrame([(4, -4, -2)], ('C1', 'C2', 'C3'))
>>> df2.select(sequence('C1', 'C2', 'C3').alias('r')).collect()
[Row(r=[4, 2, 0, -2, -4])]
"""
sc = SparkContext._active_spark_context
if step is None:
return Column(sc._jvm.functions.sequence(_to_java_column(start), _to_java_column(stop)))
else:
return Column(sc._jvm.functions.sequence(
_to_java_column(start), _to_java_column(stop), _to_java_column(step))) |
Parses a column containing a CSV string to a row with the specified schema. Returns null in the case of an unparseable string. | def from_csv(col, schema, options={}):
"""
Parses a column containing a CSV string to a row with the specified schema.
Returns `null`, in the case of an unparseable string.
:param col: string column in CSV format
:param schema: a string with schema in DDL format to use when parsing the CSV column.
:param options: options to control parsing. accepts the same options as the CSV datasource
>>> data = [("1,2,3",)]
>>> df = spark.createDataFrame(data, ("value",))
>>> df.select(from_csv(df.value, "a INT, b INT, c INT").alias("csv")).collect()
[Row(csv=Row(a=1, b=2, c=3))]
>>> value = data[0][0]
>>> df.select(from_csv(df.value, schema_of_csv(value)).alias("csv")).collect()
[Row(csv=Row(_c0=1, _c1=2, _c2=3))]
"""
sc = SparkContext._active_spark_context
if isinstance(schema, basestring):
schema = _create_column_from_literal(schema)
elif isinstance(schema, Column):
schema = _to_java_column(schema)
else:
raise TypeError("schema argument should be a column or string")
jc = sc._jvm.functions.from_csv(_to_java_column(col), schema, options)
return Column(jc) |
Creates a user defined function ( UDF ). | def udf(f=None, returnType=StringType()):
"""Creates a user defined function (UDF).
.. note:: The user-defined functions are considered deterministic by default. Due to
optimization, duplicate invocations may be eliminated or the function may even be invoked
more times than it is present in the query. If your function is not deterministic, call
`asNondeterministic` on the user defined function. E.g.:
>>> from pyspark.sql.types import IntegerType
>>> import random
>>> random_udf = udf(lambda: int(random.random() * 100), IntegerType()).asNondeterministic()
.. note:: The user-defined functions do not support conditional expressions or short circuiting
in boolean expressions and it ends up with being executed all internally. If the functions
can fail on special rows, the workaround is to incorporate the condition into the functions.
.. note:: The user-defined functions do not take keyword arguments on the calling side.
:param f: python function if used as a standalone function
:param returnType: the return type of the user-defined function. The value can be either a
:class:`pyspark.sql.types.DataType` object or a DDL-formatted type string.
>>> from pyspark.sql.types import IntegerType
>>> slen = udf(lambda s: len(s), IntegerType())
>>> @udf
... def to_upper(s):
... if s is not None:
... return s.upper()
...
>>> @udf(returnType=IntegerType())
... def add_one(x):
... if x is not None:
... return x + 1
...
>>> df = spark.createDataFrame([(1, "John Doe", 21)], ("id", "name", "age"))
>>> df.select(slen("name").alias("slen(name)"), to_upper("name"), add_one("age")).show()
+----------+--------------+------------+
|slen(name)|to_upper(name)|add_one(age)|
+----------+--------------+------------+
| 8| JOHN DOE| 22|
+----------+--------------+------------+
"""
# The following table shows most of Python data and SQL type conversions in normal UDFs that
# are not yet visible to the user. Some of behaviors are buggy and might be changed in the near
# future. The table might have to be eventually documented externally.
# Please see SPARK-25666's PR to see the codes in order to generate the table below.
#
# +-----------------------------+--------------+----------+------+-------+---------------+---------------+--------------------+-----------------------------+----------+----------------------+---------+--------------------+-----------------+------------+--------------+------------------+----------------------+ # noqa
# |SQL Type \ Python Value(Type)|None(NoneType)|True(bool)|1(int)|1(long)| a(str)| a(unicode)| 1970-01-01(date)|1970-01-01 00:00:00(datetime)|1.0(float)|array('i', [1])(array)|[1](list)| (1,)(tuple)| ABC(bytearray)| 1(Decimal)|{'a': 1}(dict)|Row(kwargs=1)(Row)|Row(namedtuple=1)(Row)| # noqa
# +-----------------------------+--------------+----------+------+-------+---------------+---------------+--------------------+-----------------------------+----------+----------------------+---------+--------------------+-----------------+------------+--------------+------------------+----------------------+ # noqa
# | boolean| None| True| None| None| None| None| None| None| None| None| None| None| None| None| None| X| X| # noqa
# | tinyint| None| None| 1| 1| None| None| None| None| None| None| None| None| None| None| None| X| X| # noqa
# | smallint| None| None| 1| 1| None| None| None| None| None| None| None| None| None| None| None| X| X| # noqa
# | int| None| None| 1| 1| None| None| None| None| None| None| None| None| None| None| None| X| X| # noqa
# | bigint| None| None| 1| 1| None| None| None| None| None| None| None| None| None| None| None| X| X| # noqa
# | string| None| u'true'| u'1'| u'1'| u'a'| u'a'|u'java.util.Grego...| u'java.util.Grego...| u'1.0'| u'[I@24a83055'| u'[1]'|u'[Ljava.lang.Obj...| u'[B@49093632'| u'1'| u'{a=1}'| X| X| # noqa
# | date| None| X| X| X| X| X|datetime.date(197...| datetime.date(197...| X| X| X| X| X| X| X| X| X| # noqa
# | timestamp| None| X| X| X| X| X| X| datetime.datetime...| X| X| X| X| X| X| X| X| X| # noqa
# | float| None| None| None| None| None| None| None| None| 1.0| None| None| None| None| None| None| X| X| # noqa
# | double| None| None| None| None| None| None| None| None| 1.0| None| None| None| None| None| None| X| X| # noqa
# | array<int>| None| None| None| None| None| None| None| None| None| [1]| [1]| [1]| [65, 66, 67]| None| None| X| X| # noqa
# | binary| None| None| None| None|bytearray(b'a')|bytearray(b'a')| None| None| None| None| None| None|bytearray(b'ABC')| None| None| X| X| # noqa
# | decimal(10,0)| None| None| None| None| None| None| None| None| None| None| None| None| None|Decimal('1')| None| X| X| # noqa
# | map<string,int>| None| None| None| None| None| None| None| None| None| None| None| None| None| None| {u'a': 1}| X| X| # noqa
# | struct<_1:int>| None| X| X| X| X| X| X| X| X| X|Row(_1=1)| Row(_1=1)| X| X| Row(_1=None)| Row(_1=1)| Row(_1=1)| # noqa
# +-----------------------------+--------------+----------+------+-------+---------------+---------------+--------------------+-----------------------------+----------+----------------------+---------+--------------------+-----------------+------------+--------------+------------------+----------------------+ # noqa
#
# Note: DDL formatted string is used for 'SQL Type' for simplicity. This string can be
# used in `returnType`.
# Note: The values inside of the table are generated by `repr`.
# Note: Python 2 is used to generate this table since it is used to check the backward
# compatibility often in practice.
# Note: 'X' means it throws an exception during the conversion.
# decorator @udf, @udf(), @udf(dataType())
if f is None or isinstance(f, (str, DataType)):
# If DataType has been passed as a positional argument
# for decorator use it as a returnType
return_type = f or returnType
return functools.partial(_create_udf, returnType=return_type,
evalType=PythonEvalType.SQL_BATCHED_UDF)
else:
return _create_udf(f=f, returnType=returnType,
evalType=PythonEvalType.SQL_BATCHED_UDF) |
Creates a vectorized user defined function ( UDF ). | def pandas_udf(f=None, returnType=None, functionType=None):
"""
Creates a vectorized user defined function (UDF).
:param f: user-defined function. A python function if used as a standalone function
:param returnType: the return type of the user-defined function. The value can be either a
:class:`pyspark.sql.types.DataType` object or a DDL-formatted type string.
:param functionType: an enum value in :class:`pyspark.sql.functions.PandasUDFType`.
Default: SCALAR.
.. note:: Experimental
The function type of the UDF can be one of the following:
1. SCALAR
A scalar UDF defines a transformation: One or more `pandas.Series` -> A `pandas.Series`.
The length of the returned `pandas.Series` must be of the same as the input `pandas.Series`.
If the return type is :class:`StructType`, the returned value should be a `pandas.DataFrame`.
:class:`MapType`, nested :class:`StructType` are currently not supported as output types.
Scalar UDFs are used with :meth:`pyspark.sql.DataFrame.withColumn` and
:meth:`pyspark.sql.DataFrame.select`.
>>> from pyspark.sql.functions import pandas_udf, PandasUDFType
>>> from pyspark.sql.types import IntegerType, StringType
>>> slen = pandas_udf(lambda s: s.str.len(), IntegerType()) # doctest: +SKIP
>>> @pandas_udf(StringType()) # doctest: +SKIP
... def to_upper(s):
... return s.str.upper()
...
>>> @pandas_udf("integer", PandasUDFType.SCALAR) # doctest: +SKIP
... def add_one(x):
... return x + 1
...
>>> df = spark.createDataFrame([(1, "John Doe", 21)],
... ("id", "name", "age")) # doctest: +SKIP
>>> df.select(slen("name").alias("slen(name)"), to_upper("name"), add_one("age")) \\
... .show() # doctest: +SKIP
+----------+--------------+------------+
|slen(name)|to_upper(name)|add_one(age)|
+----------+--------------+------------+
| 8| JOHN DOE| 22|
+----------+--------------+------------+
>>> @pandas_udf("first string, last string") # doctest: +SKIP
... def split_expand(n):
... return n.str.split(expand=True)
>>> df.select(split_expand("name")).show() # doctest: +SKIP
+------------------+
|split_expand(name)|
+------------------+
| [John, Doe]|
+------------------+
.. note:: The length of `pandas.Series` within a scalar UDF is not that of the whole input
column, but is the length of an internal batch used for each call to the function.
Therefore, this can be used, for example, to ensure the length of each returned
`pandas.Series`, and can not be used as the column length.
2. GROUPED_MAP
A grouped map UDF defines transformation: A `pandas.DataFrame` -> A `pandas.DataFrame`
The returnType should be a :class:`StructType` describing the schema of the returned
`pandas.DataFrame`. The column labels of the returned `pandas.DataFrame` must either match
the field names in the defined returnType schema if specified as strings, or match the
field data types by position if not strings, e.g. integer indices.
The length of the returned `pandas.DataFrame` can be arbitrary.
Grouped map UDFs are used with :meth:`pyspark.sql.GroupedData.apply`.
>>> from pyspark.sql.functions import pandas_udf, PandasUDFType
>>> df = spark.createDataFrame(
... [(1, 1.0), (1, 2.0), (2, 3.0), (2, 5.0), (2, 10.0)],
... ("id", "v")) # doctest: +SKIP
>>> @pandas_udf("id long, v double", PandasUDFType.GROUPED_MAP) # doctest: +SKIP
... def normalize(pdf):
... v = pdf.v
... return pdf.assign(v=(v - v.mean()) / v.std())
>>> df.groupby("id").apply(normalize).show() # doctest: +SKIP
+---+-------------------+
| id| v|
+---+-------------------+
| 1|-0.7071067811865475|
| 1| 0.7071067811865475|
| 2|-0.8320502943378437|
| 2|-0.2773500981126146|
| 2| 1.1094003924504583|
+---+-------------------+
Alternatively, the user can define a function that takes two arguments.
In this case, the grouping key(s) will be passed as the first argument and the data will
be passed as the second argument. The grouping key(s) will be passed as a tuple of numpy
data types, e.g., `numpy.int32` and `numpy.float64`. The data will still be passed in
as a `pandas.DataFrame` containing all columns from the original Spark DataFrame.
This is useful when the user does not want to hardcode grouping key(s) in the function.
>>> import pandas as pd # doctest: +SKIP
>>> from pyspark.sql.functions import pandas_udf, PandasUDFType
>>> df = spark.createDataFrame(
... [(1, 1.0), (1, 2.0), (2, 3.0), (2, 5.0), (2, 10.0)],
... ("id", "v")) # doctest: +SKIP
>>> @pandas_udf("id long, v double", PandasUDFType.GROUPED_MAP) # doctest: +SKIP
... def mean_udf(key, pdf):
... # key is a tuple of one numpy.int64, which is the value
... # of 'id' for the current group
... return pd.DataFrame([key + (pdf.v.mean(),)])
>>> df.groupby('id').apply(mean_udf).show() # doctest: +SKIP
+---+---+
| id| v|
+---+---+
| 1|1.5|
| 2|6.0|
+---+---+
>>> @pandas_udf(
... "id long, `ceil(v / 2)` long, v double",
... PandasUDFType.GROUPED_MAP) # doctest: +SKIP
>>> def sum_udf(key, pdf):
... # key is a tuple of two numpy.int64s, which is the values
... # of 'id' and 'ceil(df.v / 2)' for the current group
... return pd.DataFrame([key + (pdf.v.sum(),)])
>>> df.groupby(df.id, ceil(df.v / 2)).apply(sum_udf).show() # doctest: +SKIP
+---+-----------+----+
| id|ceil(v / 2)| v|
+---+-----------+----+
| 2| 5|10.0|
| 1| 1| 3.0|
| 2| 3| 5.0|
| 2| 2| 3.0|
+---+-----------+----+
.. note:: If returning a new `pandas.DataFrame` constructed with a dictionary, it is
recommended to explicitly index the columns by name to ensure the positions are correct,
or alternatively use an `OrderedDict`.
For example, `pd.DataFrame({'id': ids, 'a': data}, columns=['id', 'a'])` or
`pd.DataFrame(OrderedDict([('id', ids), ('a', data)]))`.
.. seealso:: :meth:`pyspark.sql.GroupedData.apply`
3. GROUPED_AGG
A grouped aggregate UDF defines a transformation: One or more `pandas.Series` -> A scalar
The `returnType` should be a primitive data type, e.g., :class:`DoubleType`.
The returned scalar can be either a python primitive type, e.g., `int` or `float`
or a numpy data type, e.g., `numpy.int64` or `numpy.float64`.
:class:`MapType` and :class:`StructType` are currently not supported as output types.
Group aggregate UDFs are used with :meth:`pyspark.sql.GroupedData.agg` and
:class:`pyspark.sql.Window`
This example shows using grouped aggregated UDFs with groupby:
>>> from pyspark.sql.functions import pandas_udf, PandasUDFType
>>> df = spark.createDataFrame(
... [(1, 1.0), (1, 2.0), (2, 3.0), (2, 5.0), (2, 10.0)],
... ("id", "v"))
>>> @pandas_udf("double", PandasUDFType.GROUPED_AGG) # doctest: +SKIP
... def mean_udf(v):
... return v.mean()
>>> df.groupby("id").agg(mean_udf(df['v'])).show() # doctest: +SKIP
+---+-----------+
| id|mean_udf(v)|
+---+-----------+
| 1| 1.5|
| 2| 6.0|
+---+-----------+
This example shows using grouped aggregated UDFs as window functions.
>>> from pyspark.sql.functions import pandas_udf, PandasUDFType
>>> from pyspark.sql import Window
>>> df = spark.createDataFrame(
... [(1, 1.0), (1, 2.0), (2, 3.0), (2, 5.0), (2, 10.0)],
... ("id", "v"))
>>> @pandas_udf("double", PandasUDFType.GROUPED_AGG) # doctest: +SKIP
... def mean_udf(v):
... return v.mean()
>>> w = (Window.partitionBy('id')
... .orderBy('v')
... .rowsBetween(-1, 0))
>>> df.withColumn('mean_v', mean_udf(df['v']).over(w)).show() # doctest: +SKIP
+---+----+------+
| id| v|mean_v|
+---+----+------+
| 1| 1.0| 1.0|
| 1| 2.0| 1.5|
| 2| 3.0| 3.0|
| 2| 5.0| 4.0|
| 2|10.0| 7.5|
+---+----+------+
.. note:: For performance reasons, the input series to window functions are not copied.
Therefore, mutating the input series is not allowed and will cause incorrect results.
For the same reason, users should also not rely on the index of the input series.
.. seealso:: :meth:`pyspark.sql.GroupedData.agg` and :class:`pyspark.sql.Window`
.. note:: The user-defined functions are considered deterministic by default. Due to
optimization, duplicate invocations may be eliminated or the function may even be invoked
more times than it is present in the query. If your function is not deterministic, call
`asNondeterministic` on the user defined function. E.g.:
>>> @pandas_udf('double', PandasUDFType.SCALAR) # doctest: +SKIP
... def random(v):
... import numpy as np
... import pandas as pd
... return pd.Series(np.random.randn(len(v))
>>> random = random.asNondeterministic() # doctest: +SKIP
.. note:: The user-defined functions do not support conditional expressions or short circuiting
in boolean expressions and it ends up with being executed all internally. If the functions
can fail on special rows, the workaround is to incorporate the condition into the functions.
.. note:: The user-defined functions do not take keyword arguments on the calling side.
.. note:: The data type of returned `pandas.Series` from the user-defined functions should be
matched with defined returnType (see :meth:`types.to_arrow_type` and
:meth:`types.from_arrow_type`). When there is mismatch between them, Spark might do
conversion on returned data. The conversion is not guaranteed to be correct and results
should be checked for accuracy by users.
"""
# The following table shows most of Pandas data and SQL type conversions in Pandas UDFs that
# are not yet visible to the user. Some of behaviors are buggy and might be changed in the near
# future. The table might have to be eventually documented externally.
# Please see SPARK-25798's PR to see the codes in order to generate the table below.
#
# +-----------------------------+----------------------+----------+-------+--------+--------------------+--------------------+--------+---------+---------+---------+------------+------------+------------+-----------------------------------+-----------------------------------------------------+-----------------+--------------------+-----------------------------+-------------+-----------------+------------------+-----------+--------------------------------+ # noqa
# |SQL Type \ Pandas Value(Type)|None(object(NoneType))|True(bool)|1(int8)|1(int16)| 1(int32)| 1(int64)|1(uint8)|1(uint16)|1(uint32)|1(uint64)|1.0(float16)|1.0(float32)|1.0(float64)|1970-01-01 00:00:00(datetime64[ns])|1970-01-01 00:00:00-05:00(datetime64[ns, US/Eastern])|a(object(string))| 1(object(Decimal))|[1 2 3](object(array[int32]))|1.0(float128)|(1+0j)(complex64)|(1+0j)(complex128)|A(category)|1 days 00:00:00(timedelta64[ns])| # noqa
# +-----------------------------+----------------------+----------+-------+--------+--------------------+--------------------+--------+---------+---------+---------+------------+------------+------------+-----------------------------------+-----------------------------------------------------+-----------------+--------------------+-----------------------------+-------------+-----------------+------------------+-----------+--------------------------------+ # noqa
# | boolean| None| True| True| True| True| True| True| True| True| True| False| False| False| False| False| X| X| X| False| False| False| X| False| # noqa
# | tinyint| None| 1| 1| 1| 1| 1| X| X| X| X| 1| 1| 1| X| X| X| X| X| X| X| X| 0| X| # noqa
# | smallint| None| 1| 1| 1| 1| 1| 1| X| X| X| 1| 1| 1| X| X| X| X| X| X| X| X| X| X| # noqa
# | int| None| 1| 1| 1| 1| 1| 1| 1| X| X| 1| 1| 1| X| X| X| X| X| X| X| X| X| X| # noqa
# | bigint| None| 1| 1| 1| 1| 1| 1| 1| 1| X| 1| 1| 1| 0| 18000000000000| X| X| X| X| X| X| X| X| # noqa
# | float| None| 1.0| 1.0| 1.0| 1.0| 1.0| 1.0| 1.0| 1.0| 1.0| 1.0| 1.0| 1.0| X| X| X|1.401298464324817...| X| X| X| X| X| X| # noqa
# | double| None| 1.0| 1.0| 1.0| 1.0| 1.0| 1.0| 1.0| 1.0| 1.0| 1.0| 1.0| 1.0| X| X| X| X| X| X| X| X| X| X| # noqa
# | date| None| X| X| X|datetime.date(197...| X| X| X| X| X| X| X| X| datetime.date(197...| X| X| X| X| X| X| X| X| X| # noqa
# | timestamp| None| X| X| X| X|datetime.datetime...| X| X| X| X| X| X| X| datetime.datetime...| datetime.datetime...| X| X| X| X| X| X| X| X| # noqa
# | string| None| u''|u'\x01'| u'\x01'| u'\x01'| u'\x01'| u'\x01'| u'\x01'| u'\x01'| u'\x01'| u''| u''| u''| X| X| u'a'| X| X| u''| u''| u''| X| X| # noqa
# | decimal(10,0)| None| X| X| X| X| X| X| X| X| X| X| X| X| X| X| X| Decimal('1')| X| X| X| X| X| X| # noqa
# | array<int>| None| X| X| X| X| X| X| X| X| X| X| X| X| X| X| X| X| [1, 2, 3]| X| X| X| X| X| # noqa
# | map<string,int>| X| X| X| X| X| X| X| X| X| X| X| X| X| X| X| X| X| X| X| X| X| X| X| # noqa
# | struct<_1:int>| X| X| X| X| X| X| X| X| X| X| X| X| X| X| X| X| X| X| X| X| X| X| X| # noqa
# | binary| X| X| X| X| X| X| X| X| X| X| X| X| X| X| X| X| X| X| X| X| X| X| X| # noqa
# +-----------------------------+----------------------+----------+-------+--------+--------------------+--------------------+--------+---------+---------+---------+------------+------------+------------+-----------------------------------+-----------------------------------------------------+-----------------+--------------------+-----------------------------+-------------+-----------------+------------------+-----------+--------------------------------+ # noqa
#
# Note: DDL formatted string is used for 'SQL Type' for simplicity. This string can be
# used in `returnType`.
# Note: The values inside of the table are generated by `repr`.
# Note: Python 2 is used to generate this table since it is used to check the backward
# compatibility often in practice.
# Note: Pandas 0.19.2 and PyArrow 0.9.0 are used.
# Note: Timezone is Singapore timezone.
# Note: 'X' means it throws an exception during the conversion.
# Note: 'binary' type is only supported with PyArrow 0.10.0+ (SPARK-23555).
# decorator @pandas_udf(returnType, functionType)
is_decorator = f is None or isinstance(f, (str, DataType))
if is_decorator:
# If DataType has been passed as a positional argument
# for decorator use it as a returnType
return_type = f or returnType
if functionType is not None:
# @pandas_udf(dataType, functionType=functionType)
# @pandas_udf(returnType=dataType, functionType=functionType)
eval_type = functionType
elif returnType is not None and isinstance(returnType, int):
# @pandas_udf(dataType, functionType)
eval_type = returnType
else:
# @pandas_udf(dataType) or @pandas_udf(returnType=dataType)
eval_type = PythonEvalType.SQL_SCALAR_PANDAS_UDF
else:
return_type = returnType
if functionType is not None:
eval_type = functionType
else:
eval_type = PythonEvalType.SQL_SCALAR_PANDAS_UDF
if return_type is None:
raise ValueError("Invalid returnType: returnType can not be None")
if eval_type not in [PythonEvalType.SQL_SCALAR_PANDAS_UDF,
PythonEvalType.SQL_GROUPED_MAP_PANDAS_UDF,
PythonEvalType.SQL_GROUPED_AGG_PANDAS_UDF]:
raise ValueError("Invalid functionType: "
"functionType must be one the values from PandasUDFType")
if is_decorator:
return functools.partial(_create_udf, returnType=return_type, evalType=eval_type)
else:
return _create_udf(f=f, returnType=return_type, evalType=eval_type) |
A wrapper over str () but converts bool values to lower case strings. If None is given just returns None instead of converting it to string None. | def to_str(value):
"""
A wrapper over str(), but converts bool values to lower case strings.
If None is given, just returns None, instead of converting it to string "None".
"""
if isinstance(value, bool):
return str(value).lower()
elif value is None:
return value
else:
return str(value) |
Set named options ( filter out those the value is None ) | def _set_opts(self, schema=None, **options):
"""
Set named options (filter out those the value is None)
"""
if schema is not None:
self.schema(schema)
for k, v in options.items():
if v is not None:
self.option(k, v) |
Specifies the input data source format. | def format(self, source):
"""Specifies the input data source format.
:param source: string, name of the data source, e.g. 'json', 'parquet'.
>>> df = spark.read.format('json').load('python/test_support/sql/people.json')
>>> df.dtypes
[('age', 'bigint'), ('name', 'string')]
"""
self._jreader = self._jreader.format(source)
return self |
Specifies the input schema. | def schema(self, schema):
"""Specifies the input schema.
Some data sources (e.g. JSON) can infer the input schema automatically from data.
By specifying the schema here, the underlying data source can skip the schema
inference step, and thus speed up data loading.
:param schema: a :class:`pyspark.sql.types.StructType` object or a DDL-formatted string
(For example ``col0 INT, col1 DOUBLE``).
>>> s = spark.read.schema("col0 INT, col1 DOUBLE")
"""
from pyspark.sql import SparkSession
spark = SparkSession.builder.getOrCreate()
if isinstance(schema, StructType):
jschema = spark._jsparkSession.parseDataType(schema.json())
self._jreader = self._jreader.schema(jschema)
elif isinstance(schema, basestring):
self._jreader = self._jreader.schema(schema)
else:
raise TypeError("schema should be StructType or string")
return self |
Adds an input option for the underlying data source. | def option(self, key, value):
"""Adds an input option for the underlying data source.
You can set the following option(s) for reading files:
* ``timeZone``: sets the string that indicates a timezone to be used to parse timestamps
in the JSON/CSV datasources or partition values.
If it isn't set, it uses the default value, session local timezone.
"""
self._jreader = self._jreader.option(key, to_str(value))
return self |
Adds input options for the underlying data source. | def options(self, **options):
"""Adds input options for the underlying data source.
You can set the following option(s) for reading files:
* ``timeZone``: sets the string that indicates a timezone to be used to parse timestamps
in the JSON/CSV datasources or partition values.
If it isn't set, it uses the default value, session local timezone.
"""
for k in options:
self._jreader = self._jreader.option(k, to_str(options[k]))
return self |
Loads data from a data source and returns it as a: class DataFrame. | def load(self, path=None, format=None, schema=None, **options):
"""Loads data from a data source and returns it as a :class`DataFrame`.
:param path: optional string or a list of string for file-system backed data sources.
:param format: optional string for format of the data source. Default to 'parquet'.
:param schema: optional :class:`pyspark.sql.types.StructType` for the input schema
or a DDL-formatted string (For example ``col0 INT, col1 DOUBLE``).
:param options: all other string options
>>> df = spark.read.format("parquet").load('python/test_support/sql/parquet_partitioned',
... opt1=True, opt2=1, opt3='str')
>>> df.dtypes
[('name', 'string'), ('year', 'int'), ('month', 'int'), ('day', 'int')]
>>> df = spark.read.format('json').load(['python/test_support/sql/people.json',
... 'python/test_support/sql/people1.json'])
>>> df.dtypes
[('age', 'bigint'), ('aka', 'string'), ('name', 'string')]
"""
if format is not None:
self.format(format)
if schema is not None:
self.schema(schema)
self.options(**options)
if isinstance(path, basestring):
return self._df(self._jreader.load(path))
elif path is not None:
if type(path) != list:
path = [path]
return self._df(self._jreader.load(self._spark._sc._jvm.PythonUtils.toSeq(path)))
else:
return self._df(self._jreader.load()) |
Loads JSON files and returns the results as a: class: DataFrame. | def json(self, path, schema=None, primitivesAsString=None, prefersDecimal=None,
allowComments=None, allowUnquotedFieldNames=None, allowSingleQuotes=None,
allowNumericLeadingZero=None, allowBackslashEscapingAnyCharacter=None,
mode=None, columnNameOfCorruptRecord=None, dateFormat=None, timestampFormat=None,
multiLine=None, allowUnquotedControlChars=None, lineSep=None, samplingRatio=None,
dropFieldIfAllNull=None, encoding=None, locale=None):
"""
Loads JSON files and returns the results as a :class:`DataFrame`.
`JSON Lines <http://jsonlines.org/>`_ (newline-delimited JSON) is supported by default.
For JSON (one record per file), set the ``multiLine`` parameter to ``true``.
If the ``schema`` parameter is not specified, this function goes
through the input once to determine the input schema.
:param path: string represents path to the JSON dataset, or a list of paths,
or RDD of Strings storing JSON objects.
:param schema: an optional :class:`pyspark.sql.types.StructType` for the input schema or
a DDL-formatted string (For example ``col0 INT, col1 DOUBLE``).
:param primitivesAsString: infers all primitive values as a string type. If None is set,
it uses the default value, ``false``.
:param prefersDecimal: infers all floating-point values as a decimal type. If the values
do not fit in decimal, then it infers them as doubles. If None is
set, it uses the default value, ``false``.
:param allowComments: ignores Java/C++ style comment in JSON records. If None is set,
it uses the default value, ``false``.
:param allowUnquotedFieldNames: allows unquoted JSON field names. If None is set,
it uses the default value, ``false``.
:param allowSingleQuotes: allows single quotes in addition to double quotes. If None is
set, it uses the default value, ``true``.
:param allowNumericLeadingZero: allows leading zeros in numbers (e.g. 00012). If None is
set, it uses the default value, ``false``.
:param allowBackslashEscapingAnyCharacter: allows accepting quoting of all character
using backslash quoting mechanism. If None is
set, it uses the default value, ``false``.
:param mode: allows a mode for dealing with corrupt records during parsing. If None is
set, it uses the default value, ``PERMISSIVE``.
* ``PERMISSIVE`` : when it meets a corrupted record, puts the malformed string \
into a field configured by ``columnNameOfCorruptRecord``, and sets malformed \
fields to ``null``. To keep corrupt records, an user can set a string type \
field named ``columnNameOfCorruptRecord`` in an user-defined schema. If a \
schema does not have the field, it drops corrupt records during parsing. \
When inferring a schema, it implicitly adds a ``columnNameOfCorruptRecord`` \
field in an output schema.
* ``DROPMALFORMED`` : ignores the whole corrupted records.
* ``FAILFAST`` : throws an exception when it meets corrupted records.
:param columnNameOfCorruptRecord: allows renaming the new field having malformed string
created by ``PERMISSIVE`` mode. This overrides
``spark.sql.columnNameOfCorruptRecord``. If None is set,
it uses the value specified in
``spark.sql.columnNameOfCorruptRecord``.
:param dateFormat: sets the string that indicates a date format. Custom date formats
follow the formats at ``java.time.format.DateTimeFormatter``. This
applies to date type. If None is set, it uses the
default value, ``yyyy-MM-dd``.
:param timestampFormat: sets the string that indicates a timestamp format.
Custom date formats follow the formats at
``java.time.format.DateTimeFormatter``.
This applies to timestamp type. If None is set, it uses the
default value, ``yyyy-MM-dd'T'HH:mm:ss.SSSXXX``.
:param multiLine: parse one record, which may span multiple lines, per file. If None is
set, it uses the default value, ``false``.
:param allowUnquotedControlChars: allows JSON Strings to contain unquoted control
characters (ASCII characters with value less than 32,
including tab and line feed characters) or not.
:param encoding: allows to forcibly set one of standard basic or extended encoding for
the JSON files. For example UTF-16BE, UTF-32LE. If None is set,
the encoding of input JSON will be detected automatically
when the multiLine option is set to ``true``.
:param lineSep: defines the line separator that should be used for parsing. If None is
set, it covers all ``\\r``, ``\\r\\n`` and ``\\n``.
:param samplingRatio: defines fraction of input JSON objects used for schema inferring.
If None is set, it uses the default value, ``1.0``.
:param dropFieldIfAllNull: whether to ignore column of all null values or empty
array/struct during schema inference. If None is set, it
uses the default value, ``false``.
:param locale: sets a locale as language tag in IETF BCP 47 format. If None is set,
it uses the default value, ``en-US``. For instance, ``locale`` is used while
parsing dates and timestamps.
>>> df1 = spark.read.json('python/test_support/sql/people.json')
>>> df1.dtypes
[('age', 'bigint'), ('name', 'string')]
>>> rdd = sc.textFile('python/test_support/sql/people.json')
>>> df2 = spark.read.json(rdd)
>>> df2.dtypes
[('age', 'bigint'), ('name', 'string')]
"""
self._set_opts(
schema=schema, primitivesAsString=primitivesAsString, prefersDecimal=prefersDecimal,
allowComments=allowComments, allowUnquotedFieldNames=allowUnquotedFieldNames,
allowSingleQuotes=allowSingleQuotes, allowNumericLeadingZero=allowNumericLeadingZero,
allowBackslashEscapingAnyCharacter=allowBackslashEscapingAnyCharacter,
mode=mode, columnNameOfCorruptRecord=columnNameOfCorruptRecord, dateFormat=dateFormat,
timestampFormat=timestampFormat, multiLine=multiLine,
allowUnquotedControlChars=allowUnquotedControlChars, lineSep=lineSep,
samplingRatio=samplingRatio, dropFieldIfAllNull=dropFieldIfAllNull, encoding=encoding,
locale=locale)
if isinstance(path, basestring):
path = [path]
if type(path) == list:
return self._df(self._jreader.json(self._spark._sc._jvm.PythonUtils.toSeq(path)))
elif isinstance(path, RDD):
def func(iterator):
for x in iterator:
if not isinstance(x, basestring):
x = unicode(x)
if isinstance(x, unicode):
x = x.encode("utf-8")
yield x
keyed = path.mapPartitions(func)
keyed._bypass_serializer = True
jrdd = keyed._jrdd.map(self._spark._jvm.BytesToString())
return self._df(self._jreader.json(jrdd))
else:
raise TypeError("path can be only string, list or RDD") |
Loads Parquet files returning the result as a: class: DataFrame. | def parquet(self, *paths):
"""Loads Parquet files, returning the result as a :class:`DataFrame`.
You can set the following Parquet-specific option(s) for reading Parquet files:
* ``mergeSchema``: sets whether we should merge schemas collected from all \
Parquet part-files. This will override ``spark.sql.parquet.mergeSchema``. \
The default value is specified in ``spark.sql.parquet.mergeSchema``.
>>> df = spark.read.parquet('python/test_support/sql/parquet_partitioned')
>>> df.dtypes
[('name', 'string'), ('year', 'int'), ('month', 'int'), ('day', 'int')]
"""
return self._df(self._jreader.parquet(_to_seq(self._spark._sc, paths))) |
Loads text files and returns a: class: DataFrame whose schema starts with a string column named value and followed by partitioned columns if there are any. The text files must be encoded as UTF - 8. | def text(self, paths, wholetext=False, lineSep=None):
"""
Loads text files and returns a :class:`DataFrame` whose schema starts with a
string column named "value", and followed by partitioned columns if there
are any.
The text files must be encoded as UTF-8.
By default, each line in the text file is a new row in the resulting DataFrame.
:param paths: string, or list of strings, for input path(s).
:param wholetext: if true, read each file from input path(s) as a single row.
:param lineSep: defines the line separator that should be used for parsing. If None is
set, it covers all ``\\r``, ``\\r\\n`` and ``\\n``.
>>> df = spark.read.text('python/test_support/sql/text-test.txt')
>>> df.collect()
[Row(value=u'hello'), Row(value=u'this')]
>>> df = spark.read.text('python/test_support/sql/text-test.txt', wholetext=True)
>>> df.collect()
[Row(value=u'hello\\nthis')]
"""
self._set_opts(wholetext=wholetext, lineSep=lineSep)
if isinstance(paths, basestring):
paths = [paths]
return self._df(self._jreader.text(self._spark._sc._jvm.PythonUtils.toSeq(paths))) |
r Loads a CSV file and returns the result as a: class: DataFrame. | def csv(self, path, schema=None, sep=None, encoding=None, quote=None, escape=None,
comment=None, header=None, inferSchema=None, ignoreLeadingWhiteSpace=None,
ignoreTrailingWhiteSpace=None, nullValue=None, nanValue=None, positiveInf=None,
negativeInf=None, dateFormat=None, timestampFormat=None, maxColumns=None,
maxCharsPerColumn=None, maxMalformedLogPerPartition=None, mode=None,
columnNameOfCorruptRecord=None, multiLine=None, charToEscapeQuoteEscaping=None,
samplingRatio=None, enforceSchema=None, emptyValue=None, locale=None, lineSep=None):
r"""Loads a CSV file and returns the result as a :class:`DataFrame`.
This function will go through the input once to determine the input schema if
``inferSchema`` is enabled. To avoid going through the entire data once, disable
``inferSchema`` option or specify the schema explicitly using ``schema``.
:param path: string, or list of strings, for input path(s),
or RDD of Strings storing CSV rows.
:param schema: an optional :class:`pyspark.sql.types.StructType` for the input schema
or a DDL-formatted string (For example ``col0 INT, col1 DOUBLE``).
:param sep: sets a single character as a separator for each field and value.
If None is set, it uses the default value, ``,``.
:param encoding: decodes the CSV files by the given encoding type. If None is set,
it uses the default value, ``UTF-8``.
:param quote: sets a single character used for escaping quoted values where the
separator can be part of the value. If None is set, it uses the default
value, ``"``. If you would like to turn off quotations, you need to set an
empty string.
:param escape: sets a single character used for escaping quotes inside an already
quoted value. If None is set, it uses the default value, ``\``.
:param comment: sets a single character used for skipping lines beginning with this
character. By default (None), it is disabled.
:param header: uses the first line as names of columns. If None is set, it uses the
default value, ``false``.
:param inferSchema: infers the input schema automatically from data. It requires one extra
pass over the data. If None is set, it uses the default value, ``false``.
:param enforceSchema: If it is set to ``true``, the specified or inferred schema will be
forcibly applied to datasource files, and headers in CSV files will be
ignored. If the option is set to ``false``, the schema will be
validated against all headers in CSV files or the first header in RDD
if the ``header`` option is set to ``true``. Field names in the schema
and column names in CSV headers are checked by their positions
taking into account ``spark.sql.caseSensitive``. If None is set,
``true`` is used by default. Though the default value is ``true``,
it is recommended to disable the ``enforceSchema`` option
to avoid incorrect results.
:param ignoreLeadingWhiteSpace: A flag indicating whether or not leading whitespaces from
values being read should be skipped. If None is set, it
uses the default value, ``false``.
:param ignoreTrailingWhiteSpace: A flag indicating whether or not trailing whitespaces from
values being read should be skipped. If None is set, it
uses the default value, ``false``.
:param nullValue: sets the string representation of a null value. If None is set, it uses
the default value, empty string. Since 2.0.1, this ``nullValue`` param
applies to all supported types including the string type.
:param nanValue: sets the string representation of a non-number value. If None is set, it
uses the default value, ``NaN``.
:param positiveInf: sets the string representation of a positive infinity value. If None
is set, it uses the default value, ``Inf``.
:param negativeInf: sets the string representation of a negative infinity value. If None
is set, it uses the default value, ``Inf``.
:param dateFormat: sets the string that indicates a date format. Custom date formats
follow the formats at ``java.time.format.DateTimeFormatter``. This
applies to date type. If None is set, it uses the
default value, ``yyyy-MM-dd``.
:param timestampFormat: sets the string that indicates a timestamp format.
Custom date formats follow the formats at
``java.time.format.DateTimeFormatter``.
This applies to timestamp type. If None is set, it uses the
default value, ``yyyy-MM-dd'T'HH:mm:ss.SSSXXX``.
:param maxColumns: defines a hard limit of how many columns a record can have. If None is
set, it uses the default value, ``20480``.
:param maxCharsPerColumn: defines the maximum number of characters allowed for any given
value being read. If None is set, it uses the default value,
``-1`` meaning unlimited length.
:param maxMalformedLogPerPartition: this parameter is no longer used since Spark 2.2.0.
If specified, it is ignored.
:param mode: allows a mode for dealing with corrupt records during parsing. If None is
set, it uses the default value, ``PERMISSIVE``.
* ``PERMISSIVE`` : when it meets a corrupted record, puts the malformed string \
into a field configured by ``columnNameOfCorruptRecord``, and sets malformed \
fields to ``null``. To keep corrupt records, an user can set a string type \
field named ``columnNameOfCorruptRecord`` in an user-defined schema. If a \
schema does not have the field, it drops corrupt records during parsing. \
A record with less/more tokens than schema is not a corrupted record to CSV. \
When it meets a record having fewer tokens than the length of the schema, \
sets ``null`` to extra fields. When the record has more tokens than the \
length of the schema, it drops extra tokens.
* ``DROPMALFORMED`` : ignores the whole corrupted records.
* ``FAILFAST`` : throws an exception when it meets corrupted records.
:param columnNameOfCorruptRecord: allows renaming the new field having malformed string
created by ``PERMISSIVE`` mode. This overrides
``spark.sql.columnNameOfCorruptRecord``. If None is set,
it uses the value specified in
``spark.sql.columnNameOfCorruptRecord``.
:param multiLine: parse records, which may span multiple lines. If None is
set, it uses the default value, ``false``.
:param charToEscapeQuoteEscaping: sets a single character used for escaping the escape for
the quote character. If None is set, the default value is
escape character when escape and quote characters are
different, ``\0`` otherwise.
:param samplingRatio: defines fraction of rows used for schema inferring.
If None is set, it uses the default value, ``1.0``.
:param emptyValue: sets the string representation of an empty value. If None is set, it uses
the default value, empty string.
:param locale: sets a locale as language tag in IETF BCP 47 format. If None is set,
it uses the default value, ``en-US``. For instance, ``locale`` is used while
parsing dates and timestamps.
:param lineSep: defines the line separator that should be used for parsing. If None is
set, it covers all ``\\r``, ``\\r\\n`` and ``\\n``.
Maximum length is 1 character.
>>> df = spark.read.csv('python/test_support/sql/ages.csv')
>>> df.dtypes
[('_c0', 'string'), ('_c1', 'string')]
>>> rdd = sc.textFile('python/test_support/sql/ages.csv')
>>> df2 = spark.read.csv(rdd)
>>> df2.dtypes
[('_c0', 'string'), ('_c1', 'string')]
"""
self._set_opts(
schema=schema, sep=sep, encoding=encoding, quote=quote, escape=escape, comment=comment,
header=header, inferSchema=inferSchema, ignoreLeadingWhiteSpace=ignoreLeadingWhiteSpace,
ignoreTrailingWhiteSpace=ignoreTrailingWhiteSpace, nullValue=nullValue,
nanValue=nanValue, positiveInf=positiveInf, negativeInf=negativeInf,
dateFormat=dateFormat, timestampFormat=timestampFormat, maxColumns=maxColumns,
maxCharsPerColumn=maxCharsPerColumn,
maxMalformedLogPerPartition=maxMalformedLogPerPartition, mode=mode,
columnNameOfCorruptRecord=columnNameOfCorruptRecord, multiLine=multiLine,
charToEscapeQuoteEscaping=charToEscapeQuoteEscaping, samplingRatio=samplingRatio,
enforceSchema=enforceSchema, emptyValue=emptyValue, locale=locale, lineSep=lineSep)
if isinstance(path, basestring):
path = [path]
if type(path) == list:
return self._df(self._jreader.csv(self._spark._sc._jvm.PythonUtils.toSeq(path)))
elif isinstance(path, RDD):
def func(iterator):
for x in iterator:
if not isinstance(x, basestring):
x = unicode(x)
if isinstance(x, unicode):
x = x.encode("utf-8")
yield x
keyed = path.mapPartitions(func)
keyed._bypass_serializer = True
jrdd = keyed._jrdd.map(self._spark._jvm.BytesToString())
# see SPARK-22112
# There aren't any jvm api for creating a dataframe from rdd storing csv.
# We can do it through creating a jvm dataset firstly and using the jvm api
# for creating a dataframe from dataset storing csv.
jdataset = self._spark._ssql_ctx.createDataset(
jrdd.rdd(),
self._spark._jvm.Encoders.STRING())
return self._df(self._jreader.csv(jdataset))
else:
raise TypeError("path can be only string, list or RDD") |
Loads ORC files returning the result as a: class: DataFrame. | def orc(self, path):
"""Loads ORC files, returning the result as a :class:`DataFrame`.
>>> df = spark.read.orc('python/test_support/sql/orc_partitioned')
>>> df.dtypes
[('a', 'bigint'), ('b', 'int'), ('c', 'int')]
"""
if isinstance(path, basestring):
path = [path]
return self._df(self._jreader.orc(_to_seq(self._spark._sc, path))) |
Construct a: class: DataFrame representing the database table named table accessible via JDBC URL url and connection properties. | def jdbc(self, url, table, column=None, lowerBound=None, upperBound=None, numPartitions=None,
predicates=None, properties=None):
"""
Construct a :class:`DataFrame` representing the database table named ``table``
accessible via JDBC URL ``url`` and connection ``properties``.
Partitions of the table will be retrieved in parallel if either ``column`` or
``predicates`` is specified. ``lowerBound`, ``upperBound`` and ``numPartitions``
is needed when ``column`` is specified.
If both ``column`` and ``predicates`` are specified, ``column`` will be used.
.. note:: Don't create too many partitions in parallel on a large cluster;
otherwise Spark might crash your external database systems.
:param url: a JDBC URL of the form ``jdbc:subprotocol:subname``
:param table: the name of the table
:param column: the name of an integer column that will be used for partitioning;
if this parameter is specified, then ``numPartitions``, ``lowerBound``
(inclusive), and ``upperBound`` (exclusive) will form partition strides
for generated WHERE clause expressions used to split the column
``column`` evenly
:param lowerBound: the minimum value of ``column`` used to decide partition stride
:param upperBound: the maximum value of ``column`` used to decide partition stride
:param numPartitions: the number of partitions
:param predicates: a list of expressions suitable for inclusion in WHERE clauses;
each one defines one partition of the :class:`DataFrame`
:param properties: a dictionary of JDBC database connection arguments. Normally at
least properties "user" and "password" with their corresponding values.
For example { 'user' : 'SYSTEM', 'password' : 'mypassword' }
:return: a DataFrame
"""
if properties is None:
properties = dict()
jprop = JavaClass("java.util.Properties", self._spark._sc._gateway._gateway_client)()
for k in properties:
jprop.setProperty(k, properties[k])
if column is not None:
assert lowerBound is not None, "lowerBound can not be None when ``column`` is specified"
assert upperBound is not None, "upperBound can not be None when ``column`` is specified"
assert numPartitions is not None, \
"numPartitions can not be None when ``column`` is specified"
return self._df(self._jreader.jdbc(url, table, column, int(lowerBound), int(upperBound),
int(numPartitions), jprop))
if predicates is not None:
gateway = self._spark._sc._gateway
jpredicates = utils.toJArray(gateway, gateway.jvm.java.lang.String, predicates)
return self._df(self._jreader.jdbc(url, table, jpredicates, jprop))
return self._df(self._jreader.jdbc(url, table, jprop)) |
Specifies the behavior when data or table already exists. | def mode(self, saveMode):
"""Specifies the behavior when data or table already exists.
Options include:
* `append`: Append contents of this :class:`DataFrame` to existing data.
* `overwrite`: Overwrite existing data.
* `error` or `errorifexists`: Throw an exception if data already exists.
* `ignore`: Silently ignore this operation if data already exists.
>>> df.write.mode('append').parquet(os.path.join(tempfile.mkdtemp(), 'data'))
"""
# At the JVM side, the default value of mode is already set to "error".
# So, if the given saveMode is None, we will not call JVM-side's mode method.
if saveMode is not None:
self._jwrite = self._jwrite.mode(saveMode)
return self |
Specifies the underlying output data source. | def format(self, source):
"""Specifies the underlying output data source.
:param source: string, name of the data source, e.g. 'json', 'parquet'.
>>> df.write.format('json').save(os.path.join(tempfile.mkdtemp(), 'data'))
"""
self._jwrite = self._jwrite.format(source)
return self |
Adds an output option for the underlying data source. | def option(self, key, value):
"""Adds an output option for the underlying data source.
You can set the following option(s) for writing files:
* ``timeZone``: sets the string that indicates a timezone to be used to format
timestamps in the JSON/CSV datasources or partition values.
If it isn't set, it uses the default value, session local timezone.
"""
self._jwrite = self._jwrite.option(key, to_str(value))
return self |
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