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spark-instrumented-optimizer/python/pyspark/sql/dataframe.py
Daoyuan Wang 653db0a1bd [SPARK-6876] [PySpark] [SQL] add DataFrame na.replace in pyspark 
Author: Daoyuan Wang <daoyuan.wang@intel.com>

Closes #6003 from adrian-wang/pynareplace and squashes the following commits:

672efba [Daoyuan Wang] remove py2.7 feature
4a148f7 [Daoyuan Wang] to_replace support dict, value support single value, and add full tests
9e232e7 [Daoyuan Wang] rename scala map
af0268a [Daoyuan Wang] remove na
63ac579 [Daoyuan Wang] add na.replace in pyspark

(cherry picked from commit d86ce84584)
Signed-off-by: Reynold Xin <rxin@databricks.com>
2015-05-12 10:23:57 -07:00

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#
# Licensed to the Apache Software Foundation (ASF) under one or more
# contributor license agreements. See the NOTICE file distributed with
# this work for additional information regarding copyright ownership.
# The ASF licenses this file to You under the Apache License, Version 2.0
# (the "License"); you may not use this file except in compliance with
# the License. You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
import sys
import warnings
import random
if sys.version >= '3':
basestring = unicode = str
long = int
else:
from itertools import imap as map
from pyspark.context import SparkContext
from pyspark.rdd import RDD, _load_from_socket, ignore_unicode_prefix
from pyspark.serializers import BatchedSerializer, PickleSerializer, UTF8Deserializer
from pyspark.storagelevel import StorageLevel
from pyspark.traceback_utils import SCCallSiteSync
from pyspark.sql.types import *
from pyspark.sql.types import _create_cls, _parse_datatype_json_string
__all__ = ["DataFrame", "GroupedData", "Column", "SchemaRDD", "DataFrameNaFunctions",
"DataFrameStatFunctions"]
class DataFrame(object):
"""A distributed collection of data grouped into named columns.
A :class:`DataFrame` is equivalent to a relational table in Spark SQL,
and can be created using various functions in :class:`SQLContext`::
people = sqlContext.parquetFile("...")
Once created, it can be manipulated using the various domain-specific-language
(DSL) functions defined in: :class:`DataFrame`, :class:`Column`.
To select a column from the data frame, use the apply method::
ageCol = people.age
A more concrete example::
# To create DataFrame using SQLContext
people = sqlContext.parquetFile("...")
department = sqlContext.parquetFile("...")
people.filter(people.age > 30).join(department, people.deptId == department.id)) \
.groupBy(department.name, "gender").agg({"salary": "avg", "age": "max"})
"""
def __init__(self, jdf, sql_ctx):
self._jdf = jdf
self.sql_ctx = sql_ctx
self._sc = sql_ctx and sql_ctx._sc
self.is_cached = False
self._schema = None # initialized lazily
self._lazy_rdd = None
@property
def rdd(self):
"""Returns the content as an :class:`pyspark.RDD` of :class:`Row`.
"""
if self._lazy_rdd is None:
jrdd = self._jdf.javaToPython()
rdd = RDD(jrdd, self.sql_ctx._sc, BatchedSerializer(PickleSerializer()))
schema = self.schema
def applySchema(it):
cls = _create_cls(schema)
return map(cls, it)
self._lazy_rdd = rdd.mapPartitions(applySchema)
return self._lazy_rdd
@property
def na(self):
"""Returns a :class:`DataFrameNaFunctions` for handling missing values.
"""
return DataFrameNaFunctions(self)
@property
def stat(self):
"""Returns a :class:`DataFrameStatFunctions` for statistic functions.
"""
return DataFrameStatFunctions(self)
@ignore_unicode_prefix
def toJSON(self, use_unicode=True):
"""Converts a :class:`DataFrame` into a :class:`RDD` of string.
Each row is turned into a JSON document as one element in the returned RDD.
>>> df.toJSON().first()
u'{"age":2,"name":"Alice"}'
"""
rdd = self._jdf.toJSON()
return RDD(rdd.toJavaRDD(), self._sc, UTF8Deserializer(use_unicode))
def saveAsParquetFile(self, path):
"""Saves the contents as a Parquet file, preserving the schema.
Files that are written out using this method can be read back in as
a :class:`DataFrame` using :func:`SQLContext.parquetFile`.
>>> import tempfile, shutil
>>> parquetFile = tempfile.mkdtemp()
>>> shutil.rmtree(parquetFile)
>>> df.saveAsParquetFile(parquetFile)
>>> df2 = sqlContext.parquetFile(parquetFile)
>>> sorted(df2.collect()) == sorted(df.collect())
True
"""
self._jdf.saveAsParquetFile(path)
def registerTempTable(self, name):
"""Registers this RDD as a temporary table using the given name.
The lifetime of this temporary table is tied to the :class:`SQLContext`
that was used to create this :class:`DataFrame`.
>>> df.registerTempTable("people")
>>> df2 = sqlContext.sql("select * from people")
>>> sorted(df.collect()) == sorted(df2.collect())
True
"""
self._jdf.registerTempTable(name)
def registerAsTable(self, name):
"""DEPRECATED: use :func:`registerTempTable` instead"""
warnings.warn("Use registerTempTable instead of registerAsTable.", DeprecationWarning)
self.registerTempTable(name)
def insertInto(self, tableName, overwrite=False):
"""Inserts the contents of this :class:`DataFrame` into the specified table.
Optionally overwriting any existing data.
"""
self._jdf.insertInto(tableName, overwrite)
def _java_save_mode(self, mode):
"""Returns the Java save mode based on the Python save mode represented by a string.
"""
jSaveMode = self._sc._jvm.org.apache.spark.sql.SaveMode
jmode = jSaveMode.ErrorIfExists
mode = mode.lower()
if mode == "append":
jmode = jSaveMode.Append
elif mode == "overwrite":
jmode = jSaveMode.Overwrite
elif mode == "ignore":
jmode = jSaveMode.Ignore
elif mode == "error":
pass
else:
raise ValueError(
"Only 'append', 'overwrite', 'ignore', and 'error' are acceptable save mode.")
return jmode
def saveAsTable(self, tableName, source=None, mode="error", **options):
"""Saves the contents of this :class:`DataFrame` to a data source as a table.
The data source is specified by the ``source`` and a set of ``options``.
If ``source`` is not specified, the default data source configured by
``spark.sql.sources.default`` will be used.
Additionally, mode is used to specify the behavior of the saveAsTable operation when
table already exists in the data source. There are four modes:
* `append`: Append contents of this :class:`DataFrame` to existing data.
* `overwrite`: Overwrite existing data.
* `error`: Throw an exception if data already exists.
* `ignore`: Silently ignore this operation if data already exists.
"""
if source is None:
source = self.sql_ctx.getConf("spark.sql.sources.default",
"org.apache.spark.sql.parquet")
jmode = self._java_save_mode(mode)
self._jdf.saveAsTable(tableName, source, jmode, options)
def save(self, path=None, source=None, mode="error", **options):
"""Saves the contents of the :class:`DataFrame` to a data source.
The data source is specified by the ``source`` and a set of ``options``.
If ``source`` is not specified, the default data source configured by
``spark.sql.sources.default`` will be used.
Additionally, mode is used to specify the behavior of the save operation when
data already exists in the data source. There are four modes:
* `append`: Append contents of this :class:`DataFrame` to existing data.
* `overwrite`: Overwrite existing data.
* `error`: Throw an exception if data already exists.
* `ignore`: Silently ignore this operation if data already exists.
"""
if path is not None:
options["path"] = path
if source is None:
source = self.sql_ctx.getConf("spark.sql.sources.default",
"org.apache.spark.sql.parquet")
jmode = self._java_save_mode(mode)
self._jdf.save(source, jmode, options)
@property
def schema(self):
"""Returns the schema of this :class:`DataFrame` as a :class:`types.StructType`.
>>> df.schema
StructType(List(StructField(age,IntegerType,true),StructField(name,StringType,true)))
"""
if self._schema is None:
self._schema = _parse_datatype_json_string(self._jdf.schema().json())
return self._schema
def printSchema(self):
"""Prints out the schema in the tree format.
>>> df.printSchema()
root
|-- age: integer (nullable = true)
|-- name: string (nullable = true)
<BLANKLINE>
"""
print(self._jdf.schema().treeString())
def explain(self, extended=False):
"""Prints the (logical and physical) plans to the console for debugging purpose.
:param extended: boolean, default ``False``. If ``False``, prints only the physical plan.
>>> df.explain()
PhysicalRDD [age#0,name#1], MapPartitionsRDD[...] at applySchemaToPythonRDD at\
NativeMethodAccessorImpl.java:...
>>> df.explain(True)
== Parsed Logical Plan ==
...
== Analyzed Logical Plan ==
...
== Optimized Logical Plan ==
...
== Physical Plan ==
...
== RDD ==
"""
if extended:
print(self._jdf.queryExecution().toString())
else:
print(self._jdf.queryExecution().executedPlan().toString())
def isLocal(self):
"""Returns ``True`` if the :func:`collect` and :func:`take` methods can be run locally
(without any Spark executors).
"""
return self._jdf.isLocal()
def show(self, n=20):
"""Prints the first ``n`` rows to the console.
>>> df
DataFrame[age: int, name: string]
>>> df.show()
+---+-----+
|age| name|
+---+-----+
| 2|Alice|
| 5| Bob|
+---+-----+
"""
print(self._jdf.showString(n))
def __repr__(self):
return "DataFrame[%s]" % (", ".join("%s: %s" % c for c in self.dtypes))
def count(self):
"""Returns the number of rows in this :class:`DataFrame`.
>>> df.count()
2
"""
return int(self._jdf.count())
@ignore_unicode_prefix
def collect(self):
"""Returns all the records as a list of :class:`Row`.
>>> df.collect()
[Row(age=2, name=u'Alice'), Row(age=5, name=u'Bob')]
"""
with SCCallSiteSync(self._sc) as css:
port = self._sc._jvm.PythonRDD.collectAndServe(self._jdf.javaToPython().rdd())
rs = list(_load_from_socket(port, BatchedSerializer(PickleSerializer())))
cls = _create_cls(self.schema)
return [cls(r) for r in rs]
@ignore_unicode_prefix
def limit(self, num):
"""Limits the result count to the number specified.
>>> df.limit(1).collect()
[Row(age=2, name=u'Alice')]
>>> df.limit(0).collect()
[]
"""
jdf = self._jdf.limit(num)
return DataFrame(jdf, self.sql_ctx)
@ignore_unicode_prefix
def take(self, num):
"""Returns the first ``num`` rows as a :class:`list` of :class:`Row`.
>>> df.take(2)
[Row(age=2, name=u'Alice'), Row(age=5, name=u'Bob')]
"""
return self.limit(num).collect()
@ignore_unicode_prefix
def map(self, f):
""" Returns a new :class:`RDD` by applying a the ``f`` function to each :class:`Row`.
This is a shorthand for ``df.rdd.map()``.
>>> df.map(lambda p: p.name).collect()
[u'Alice', u'Bob']
"""
return self.rdd.map(f)
@ignore_unicode_prefix
def flatMap(self, f):
""" Returns a new :class:`RDD` by first applying the ``f`` function to each :class:`Row`,
and then flattening the results.
This is a shorthand for ``df.rdd.flatMap()``.
>>> df.flatMap(lambda p: p.name).collect()
[u'A', u'l', u'i', u'c', u'e', u'B', u'o', u'b']
"""
return self.rdd.flatMap(f)
def mapPartitions(self, f, preservesPartitioning=False):
"""Returns a new :class:`RDD` by applying the ``f`` function to each partition.
This is a shorthand for ``df.rdd.mapPartitions()``.
>>> rdd = sc.parallelize([1, 2, 3, 4], 4)
>>> def f(iterator): yield 1
>>> rdd.mapPartitions(f).sum()
4
"""
return self.rdd.mapPartitions(f, preservesPartitioning)
def foreach(self, f):
"""Applies the ``f`` function to all :class:`Row` of this :class:`DataFrame`.
This is a shorthand for ``df.rdd.foreach()``.
>>> def f(person):
... print(person.name)
>>> df.foreach(f)
"""
return self.rdd.foreach(f)
def foreachPartition(self, f):
"""Applies the ``f`` function to each partition of this :class:`DataFrame`.
This a shorthand for ``df.rdd.foreachPartition()``.
>>> def f(people):
... for person in people:
... print(person.name)
>>> df.foreachPartition(f)
"""
return self.rdd.foreachPartition(f)
def cache(self):
""" Persists with the default storage level (C{MEMORY_ONLY_SER}).
"""
self.is_cached = True
self._jdf.cache()
return self
def persist(self, storageLevel=StorageLevel.MEMORY_ONLY_SER):
"""Sets the storage level to persist its values across operations
after the first time it is computed. This can only be used to assign
a new storage level if the RDD does not have a storage level set yet.
If no storage level is specified defaults to (C{MEMORY_ONLY_SER}).
"""
self.is_cached = True
javaStorageLevel = self._sc._getJavaStorageLevel(storageLevel)
self._jdf.persist(javaStorageLevel)
return self
def unpersist(self, blocking=True):
"""Marks the :class:`DataFrame` as non-persistent, and remove all blocks for it from
memory and disk.
"""
self.is_cached = False
self._jdf.unpersist(blocking)
return self
# def coalesce(self, numPartitions, shuffle=False):
# rdd = self._jdf.coalesce(numPartitions, shuffle, None)
# return DataFrame(rdd, self.sql_ctx)
def repartition(self, numPartitions):
"""Returns a new :class:`DataFrame` that has exactly ``numPartitions`` partitions.
>>> df.repartition(10).rdd.getNumPartitions()
10
"""
return DataFrame(self._jdf.repartition(numPartitions), self.sql_ctx)
def distinct(self):
"""Returns a new :class:`DataFrame` containing the distinct rows in this :class:`DataFrame`.
>>> df.distinct().count()
2
"""
return DataFrame(self._jdf.distinct(), self.sql_ctx)
def sample(self, withReplacement, fraction, seed=None):
"""Returns a sampled subset of this :class:`DataFrame`.
>>> df.sample(False, 0.5, 42).count()
1
"""
assert fraction >= 0.0, "Negative fraction value: %s" % fraction
seed = seed if seed is not None else random.randint(0, sys.maxsize)
rdd = self._jdf.sample(withReplacement, fraction, long(seed))
return DataFrame(rdd, self.sql_ctx)
def randomSplit(self, weights, seed=None):
"""Randomly splits this :class:`DataFrame` with the provided weights.
:param weights: list of doubles as weights with which to split the DataFrame. Weights will
be normalized if they don't sum up to 1.0.
:param seed: The seed for sampling.
>>> splits = df4.randomSplit([1.0, 2.0], 24)
>>> splits[0].count()
1
>>> splits[1].count()
3
"""
for w in weights:
if w < 0.0:
raise ValueError("Weights must be positive. Found weight value: %s" % w)
seed = seed if seed is not None else random.randint(0, sys.maxsize)
rdd_array = self._jdf.randomSplit(_to_seq(self.sql_ctx._sc, weights), long(seed))
return [DataFrame(rdd, self.sql_ctx) for rdd in rdd_array]
@property
def dtypes(self):
"""Returns all column names and their data types as a list.
>>> df.dtypes
[('age', 'int'), ('name', 'string')]
"""
return [(str(f.name), f.dataType.simpleString()) for f in self.schema.fields]
@property
@ignore_unicode_prefix
def columns(self):
"""Returns all column names as a list.
>>> df.columns
[u'age', u'name']
"""
return [f.name for f in self.schema.fields]
@ignore_unicode_prefix
def alias(self, alias):
"""Returns a new :class:`DataFrame` with an alias set.
>>> from pyspark.sql.functions import *
>>> df_as1 = df.alias("df_as1")
>>> df_as2 = df.alias("df_as2")
>>> joined_df = df_as1.join(df_as2, col("df_as1.name") == col("df_as2.name"), 'inner')
>>> joined_df.select(col("df_as1.name"), col("df_as2.name"), col("df_as2.age")).collect()
[Row(name=u'Alice', name=u'Alice', age=2), Row(name=u'Bob', name=u'Bob', age=5)]
"""
assert isinstance(alias, basestring), "alias should be a string"
return DataFrame(getattr(self._jdf, "as")(alias), self.sql_ctx)
@ignore_unicode_prefix
def join(self, other, joinExprs=None, joinType=None):
"""Joins with another :class:`DataFrame`, using the given join expression.
The following performs a full outer join between ``df1`` and ``df2``.
:param other: Right side of the join
:param joinExprs: a string for join column name, or a join expression (Column).
If joinExprs is a string indicating the name of the join column,
the column must exist on both sides, and this performs an inner equi-join.
:param joinType: str, default 'inner'.
One of `inner`, `outer`, `left_outer`, `right_outer`, `semijoin`.
>>> df.join(df2, df.name == df2.name, 'outer').select(df.name, df2.height).collect()
[Row(name=None, height=80), Row(name=u'Alice', height=None), Row(name=u'Bob', height=85)]
>>> df.join(df2, 'name').select(df.name, df2.height).collect()
[Row(name=u'Bob', height=85)]
"""
if joinExprs is None:
jdf = self._jdf.join(other._jdf)
elif isinstance(joinExprs, basestring):
jdf = self._jdf.join(other._jdf, joinExprs)
else:
assert isinstance(joinExprs, Column), "joinExprs should be Column"
if joinType is None:
jdf = self._jdf.join(other._jdf, joinExprs._jc)
else:
assert isinstance(joinType, basestring), "joinType should be basestring"
jdf = self._jdf.join(other._jdf, joinExprs._jc, joinType)
return DataFrame(jdf, self.sql_ctx)
@ignore_unicode_prefix
def sort(self, *cols, **kwargs):
"""Returns a new :class:`DataFrame` sorted by the specified column(s).
:param cols: list of :class:`Column` or column names to sort by.
:param ascending: boolean or list of boolean (default True).
Sort ascending vs. descending. Specify list for multiple sort orders.
If a list is specified, length of the list must equal length of the `cols`.
>>> df.sort(df.age.desc()).collect()
[Row(age=5, name=u'Bob'), Row(age=2, name=u'Alice')]
>>> df.sort("age", ascending=False).collect()
[Row(age=5, name=u'Bob'), Row(age=2, name=u'Alice')]
>>> df.orderBy(df.age.desc()).collect()
[Row(age=5, name=u'Bob'), Row(age=2, name=u'Alice')]
>>> from pyspark.sql.functions import *
>>> df.sort(asc("age")).collect()
[Row(age=2, name=u'Alice'), Row(age=5, name=u'Bob')]
>>> df.orderBy(desc("age"), "name").collect()
[Row(age=5, name=u'Bob'), Row(age=2, name=u'Alice')]
>>> df.orderBy(["age", "name"], ascending=[0, 1]).collect()
[Row(age=5, name=u'Bob'), Row(age=2, name=u'Alice')]
"""
if not cols:
raise ValueError("should sort by at least one column")
if len(cols) == 1 and isinstance(cols[0], list):
cols = cols[0]
jcols = [_to_java_column(c) for c in cols]
ascending = kwargs.get('ascending', True)
if isinstance(ascending, (bool, int)):
if not ascending:
jcols = [jc.desc() for jc in jcols]
elif isinstance(ascending, list):
jcols = [jc if asc else jc.desc()
for asc, jc in zip(ascending, jcols)]
else:
raise TypeError("ascending can only be boolean or list, but got %s" % type(ascending))
jdf = self._jdf.sort(self._jseq(jcols))
return DataFrame(jdf, self.sql_ctx)
orderBy = sort
def _jseq(self, cols, converter=None):
"""Return a JVM Seq of Columns from a list of Column or names"""
return _to_seq(self.sql_ctx._sc, cols, converter)
def _jmap(self, jm):
"""Return a JVM Scala Map from a dict"""
return _to_scala_map(self.sql_ctx._sc, jm)
def _jcols(self, *cols):
"""Return a JVM Seq of Columns from a list of Column or column names
If `cols` has only one list in it, cols[0] will be used as the list.
"""
if len(cols) == 1 and isinstance(cols[0], list):
cols = cols[0]
return self._jseq(cols, _to_java_column)
def describe(self, *cols):
"""Computes statistics for numeric columns.
This include count, mean, stddev, min, and max. If no columns are
given, this function computes statistics for all numerical columns.
>>> df.describe().show()
+-------+---+
|summary|age|
+-------+---+
| count| 2|
| mean|3.5|
| stddev|1.5|
| min| 2|
| max| 5|
+-------+---+
"""
jdf = self._jdf.describe(self._jseq(cols))
return DataFrame(jdf, self.sql_ctx)
@ignore_unicode_prefix
def head(self, n=None):
"""
Returns the first ``n`` rows as a list of :class:`Row`,
or the first :class:`Row` if ``n`` is ``None.``
>>> df.head()
Row(age=2, name=u'Alice')
>>> df.head(1)
[Row(age=2, name=u'Alice')]
"""
if n is None:
rs = self.head(1)
return rs[0] if rs else None
return self.take(n)
@ignore_unicode_prefix
def first(self):
"""Returns the first row as a :class:`Row`.
>>> df.first()
Row(age=2, name=u'Alice')
"""
return self.head()
@ignore_unicode_prefix
def __getitem__(self, item):
"""Returns the column as a :class:`Column`.
>>> df.select(df['age']).collect()
[Row(age=2), Row(age=5)]
>>> df[ ["name", "age"]].collect()
[Row(name=u'Alice', age=2), Row(name=u'Bob', age=5)]
>>> df[ df.age > 3 ].collect()
[Row(age=5, name=u'Bob')]
>>> df[df[0] > 3].collect()
[Row(age=5, name=u'Bob')]
"""
if isinstance(item, basestring):
if item not in self.columns:
raise IndexError("no such column: %s" % item)
jc = self._jdf.apply(item)
return Column(jc)
elif isinstance(item, Column):
return self.filter(item)
elif isinstance(item, (list, tuple)):
return self.select(*item)
elif isinstance(item, int):
jc = self._jdf.apply(self.columns[item])
return Column(jc)
else:
raise TypeError("unexpected item type: %s" % type(item))
def __getattr__(self, name):
"""Returns the :class:`Column` denoted by ``name``.
>>> df.select(df.age).collect()
[Row(age=2), Row(age=5)]
"""
if name not in self.columns:
raise AttributeError(
"'%s' object has no attribute '%s'" % (self.__class__.__name__, name))
jc = self._jdf.apply(name)
return Column(jc)
@ignore_unicode_prefix
def select(self, *cols):
"""Projects a set of expressions and returns a new :class:`DataFrame`.
:param cols: list of column names (string) or expressions (:class:`Column`).
If one of the column names is '*', that column is expanded to include all columns
in the current DataFrame.
>>> df.select('*').collect()
[Row(age=2, name=u'Alice'), Row(age=5, name=u'Bob')]
>>> df.select('name', 'age').collect()
[Row(name=u'Alice', age=2), Row(name=u'Bob', age=5)]
>>> df.select(df.name, (df.age + 10).alias('age')).collect()
[Row(name=u'Alice', age=12), Row(name=u'Bob', age=15)]
"""
jdf = self._jdf.select(self._jcols(*cols))
return DataFrame(jdf, self.sql_ctx)
def selectExpr(self, *expr):
"""Projects a set of SQL expressions and returns a new :class:`DataFrame`.
This is a variant of :func:`select` that accepts SQL expressions.
>>> df.selectExpr("age * 2", "abs(age)").collect()
[Row((age * 2)=4, Abs(age)=2), Row((age * 2)=10, Abs(age)=5)]
"""
if len(expr) == 1 and isinstance(expr[0], list):
expr = expr[0]
jdf = self._jdf.selectExpr(self._jseq(expr))
return DataFrame(jdf, self.sql_ctx)
@ignore_unicode_prefix
def filter(self, condition):
"""Filters rows using the given condition.
:func:`where` is an alias for :func:`filter`.
:param condition: a :class:`Column` of :class:`types.BooleanType`
or a string of SQL expression.
>>> df.filter(df.age > 3).collect()
[Row(age=5, name=u'Bob')]
>>> df.where(df.age == 2).collect()
[Row(age=2, name=u'Alice')]
>>> df.filter("age > 3").collect()
[Row(age=5, name=u'Bob')]
>>> df.where("age = 2").collect()
[Row(age=2, name=u'Alice')]
"""
if isinstance(condition, basestring):
jdf = self._jdf.filter(condition)
elif isinstance(condition, Column):
jdf = self._jdf.filter(condition._jc)
else:
raise TypeError("condition should be string or Column")
return DataFrame(jdf, self.sql_ctx)
where = filter
@ignore_unicode_prefix
def groupBy(self, *cols):
"""Groups the :class:`DataFrame` using the specified columns,
so we can run aggregation on them. See :class:`GroupedData`
for all the available aggregate functions.
:func:`groupby` is an alias for :func:`groupBy`.
:param cols: list of columns to group by.
Each element should be a column name (string) or an expression (:class:`Column`).
>>> df.groupBy().avg().collect()
[Row(AVG(age)=3.5)]
>>> df.groupBy('name').agg({'age': 'mean'}).collect()
[Row(name=u'Alice', AVG(age)=2.0), Row(name=u'Bob', AVG(age)=5.0)]
>>> df.groupBy(df.name).avg().collect()
[Row(name=u'Alice', AVG(age)=2.0), Row(name=u'Bob', AVG(age)=5.0)]
>>> df.groupBy(['name', df.age]).count().collect()
[Row(name=u'Bob', age=5, count=1), Row(name=u'Alice', age=2, count=1)]
"""
jdf = self._jdf.groupBy(self._jcols(*cols))
return GroupedData(jdf, self.sql_ctx)
def agg(self, *exprs):
""" Aggregate on the entire :class:`DataFrame` without groups
(shorthand for ``df.groupBy.agg()``).
>>> df.agg({"age": "max"}).collect()
[Row(MAX(age)=5)]
>>> from pyspark.sql import functions as F
>>> df.agg(F.min(df.age)).collect()
[Row(MIN(age)=2)]
"""
return self.groupBy().agg(*exprs)
def unionAll(self, other):
""" Return a new :class:`DataFrame` containing union of rows in this
frame and another frame.
This is equivalent to `UNION ALL` in SQL.
"""
return DataFrame(self._jdf.unionAll(other._jdf), self.sql_ctx)
def intersect(self, other):
""" Return a new :class:`DataFrame` containing rows only in
both this frame and another frame.
This is equivalent to `INTERSECT` in SQL.
"""
return DataFrame(self._jdf.intersect(other._jdf), self.sql_ctx)
def subtract(self, other):
""" Return a new :class:`DataFrame` containing rows in this frame
but not in another frame.
This is equivalent to `EXCEPT` in SQL.
"""
return DataFrame(getattr(self._jdf, "except")(other._jdf), self.sql_ctx)
def dropDuplicates(self, subset=None):
"""Return a new :class:`DataFrame` with duplicate rows removed,
optionally only considering certain columns.
>>> from pyspark.sql import Row
>>> df = sc.parallelize([ \
Row(name='Alice', age=5, height=80), \
Row(name='Alice', age=5, height=80), \
Row(name='Alice', age=10, height=80)]).toDF()
>>> df.dropDuplicates().show()
+---+------+-----+
|age|height| name|
+---+------+-----+
| 5| 80|Alice|
| 10| 80|Alice|
+---+------+-----+
>>> df.dropDuplicates(['name', 'height']).show()
+---+------+-----+
|age|height| name|
+---+------+-----+
| 5| 80|Alice|
+---+------+-----+
"""
if subset is None:
jdf = self._jdf.dropDuplicates()
else:
jdf = self._jdf.dropDuplicates(self._jseq(subset))
return DataFrame(jdf, self.sql_ctx)
def dropna(self, how='any', thresh=None, subset=None):
"""Returns a new :class:`DataFrame` omitting rows with null values.
This is an alias for ``na.drop()``.
:param how: 'any' or 'all'.
If 'any', drop a row if it contains any nulls.
If 'all', drop a row only if all its values are null.
:param thresh: int, default None
If specified, drop rows that have less than `thresh` non-null values.
This overwrites the `how` parameter.
:param subset: optional list of column names to consider.
>>> df4.dropna().show()
+---+------+-----+
|age|height| name|
+---+------+-----+
| 10| 80|Alice|
+---+------+-----+
>>> df4.na.drop().show()
+---+------+-----+
|age|height| name|
+---+------+-----+
| 10| 80|Alice|
+---+------+-----+
"""
if how is not None and how not in ['any', 'all']:
raise ValueError("how ('" + how + "') should be 'any' or 'all'")
if subset is None:
subset = self.columns
elif isinstance(subset, basestring):
subset = [subset]
elif not isinstance(subset, (list, tuple)):
raise ValueError("subset should be a list or tuple of column names")
if thresh is None:
thresh = len(subset) if how == 'any' else 1
return DataFrame(self._jdf.na().drop(thresh, self._jseq(subset)), self.sql_ctx)
def fillna(self, value, subset=None):
"""Replace null values, alias for ``na.fill()``.
:param value: int, long, float, string, or dict.
Value to replace null values with.
If the value is a dict, then `subset` is ignored and `value` must be a mapping
from column name (string) to replacement value. The replacement value must be
an int, long, float, or string.
:param subset: optional list of column names to consider.
Columns specified in subset that do not have matching data type are ignored.
For example, if `value` is a string, and subset contains a non-string column,
then the non-string column is simply ignored.
>>> df4.fillna(50).show()
+---+------+-----+
|age|height| name|
+---+------+-----+
| 10| 80|Alice|
| 5| 50| Bob|
| 50| 50| Tom|
| 50| 50| null|
+---+------+-----+
>>> df4.fillna({'age': 50, 'name': 'unknown'}).show()
+---+------+-------+
|age|height| name|
+---+------+-------+
| 10| 80| Alice|
| 5| null| Bob|
| 50| null| Tom|
| 50| null|unknown|
+---+------+-------+
>>> df4.na.fill({'age': 50, 'name': 'unknown'}).show()
+---+------+-------+
|age|height| name|
+---+------+-------+
| 10| 80| Alice|
| 5| null| Bob|
| 50| null| Tom|
| 50| null|unknown|
+---+------+-------+
"""
if not isinstance(value, (float, int, long, basestring, dict)):
raise ValueError("value should be a float, int, long, string, or dict")
if isinstance(value, (int, long)):
value = float(value)
if isinstance(value, dict):
return DataFrame(self._jdf.na().fill(value), self.sql_ctx)
elif subset is None:
return DataFrame(self._jdf.na().fill(value), self.sql_ctx)
else:
if isinstance(subset, basestring):
subset = [subset]
elif not isinstance(subset, (list, tuple)):
raise ValueError("subset should be a list or tuple of column names")
return DataFrame(self._jdf.na().fill(value, self._jseq(subset)), self.sql_ctx)
def replace(self, to_replace, value, subset=None):
"""Returns a new :class:`DataFrame` replacing a value with another value.
:param to_replace: int, long, float, string, or list.
Value to be replaced.
If the value is a dict, then `value` is ignored and `to_replace` must be a
mapping from column name (string) to replacement value. The value to be
replaced must be an int, long, float, or string.
:param value: int, long, float, string, or list.
Value to use to replace holes.
The replacement value must be an int, long, float, or string. If `value` is a
list or tuple, `value` should be of the same length with `to_replace`.
:param subset: optional list of column names to consider.
Columns specified in subset that do not have matching data type are ignored.
For example, if `value` is a string, and subset contains a non-string column,
then the non-string column is simply ignored.
>>> df4.replace(10, 20).show()
+----+------+-----+
| age|height| name|
+----+------+-----+
| 20| 80|Alice|
| 5| null| Bob|
|null| null| Tom|
|null| null| null|
+----+------+-----+
>>> df4.replace(['Alice', 'Bob'], ['A', 'B'], 'name').show()
+----+------+----+
| age|height|name|
+----+------+----+
| 10| 80| A|
| 5| null| B|
|null| null| Tom|
|null| null|null|
+----+------+----+
"""
if not isinstance(to_replace, (float, int, long, basestring, list, tuple, dict)):
raise ValueError(
"to_replace should be a float, int, long, string, list, tuple, or dict")
if not isinstance(value, (float, int, long, basestring, list, tuple)):
raise ValueError("value should be a float, int, long, string, list, or tuple")
rep_dict = dict()
if isinstance(to_replace, (float, int, long, basestring)):
to_replace = [to_replace]
if isinstance(to_replace, tuple):
to_replace = list(to_replace)
if isinstance(value, tuple):
value = list(value)
if isinstance(to_replace, list) and isinstance(value, list):
if len(to_replace) != len(value):
raise ValueError("to_replace and value lists should be of the same length")
rep_dict = dict(zip(to_replace, value))
elif isinstance(to_replace, list) and isinstance(value, (float, int, long, basestring)):
rep_dict = dict([(tr, value) for tr in to_replace])
elif isinstance(to_replace, dict):
rep_dict = to_replace
if subset is None:
return DataFrame(self._jdf.na().replace('*', rep_dict), self.sql_ctx)
elif isinstance(subset, basestring):
subset = [subset]
if not isinstance(subset, (list, tuple)):
raise ValueError("subset should be a list or tuple of column names")
return DataFrame(
self._jdf.na().replace(self._jseq(subset), self._jmap(rep_dict)), self.sql_ctx)
def corr(self, col1, col2, method=None):
"""
Calculates the correlation of two columns of a DataFrame as a double value. Currently only
supports the Pearson Correlation Coefficient.
:func:`DataFrame.corr` and :func:`DataFrameStatFunctions.corr` are aliases.
:param col1: The name of the first column
:param col2: The name of the second column
:param method: The correlation method. Currently only supports "pearson"
"""
if not isinstance(col1, str):
raise ValueError("col1 should be a string.")
if not isinstance(col2, str):
raise ValueError("col2 should be a string.")
if not method:
method = "pearson"
if not method == "pearson":
raise ValueError("Currently only the calculation of the Pearson Correlation " +
"coefficient is supported.")
return self._jdf.stat().corr(col1, col2, method)
def cov(self, col1, col2):
"""
Calculate the sample covariance for the given columns, specified by their names, as a
double value. :func:`DataFrame.cov` and :func:`DataFrameStatFunctions.cov` are aliases.
:param col1: The name of the first column
:param col2: The name of the second column
"""
if not isinstance(col1, str):
raise ValueError("col1 should be a string.")
if not isinstance(col2, str):
raise ValueError("col2 should be a string.")
return self._jdf.stat().cov(col1, col2)
def crosstab(self, col1, col2):
"""
Computes a pair-wise frequency table of the given columns. Also known as a contingency
table. The number of distinct values for each column should be less than 1e4. At most 1e6
non-zero pair frequencies will be returned.
The first column of each row will be the distinct values of `col1` and the column names
will be the distinct values of `col2`. The name of the first column will be `$col1_$col2`.
Pairs that have no occurrences will have `null` as their counts.
:func:`DataFrame.crosstab` and :func:`DataFrameStatFunctions.crosstab` are aliases.
:param col1: The name of the first column. Distinct items will make the first item of
each row.
:param col2: The name of the second column. Distinct items will make the column names
of the DataFrame.
"""
if not isinstance(col1, str):
raise ValueError("col1 should be a string.")
if not isinstance(col2, str):
raise ValueError("col2 should be a string.")
return DataFrame(self._jdf.stat().crosstab(col1, col2), self.sql_ctx)
def freqItems(self, cols, support=None):
"""
Finding frequent items for columns, possibly with false positives. Using the
frequent element count algorithm described in
"http://dx.doi.org/10.1145/762471.762473, proposed by Karp, Schenker, and Papadimitriou".
:func:`DataFrame.freqItems` and :func:`DataFrameStatFunctions.freqItems` are aliases.
:param cols: Names of the columns to calculate frequent items for as a list or tuple of
strings.
:param support: The frequency with which to consider an item 'frequent'. Default is 1%.
The support must be greater than 1e-4.
"""
if isinstance(cols, tuple):
cols = list(cols)
if not isinstance(cols, list):
raise ValueError("cols must be a list or tuple of column names as strings.")
if not support:
support = 0.01
return DataFrame(self._jdf.stat().freqItems(_to_seq(self._sc, cols), support), self.sql_ctx)
@ignore_unicode_prefix
def withColumn(self, colName, col):
"""Returns a new :class:`DataFrame` by adding a column.
:param colName: string, name of the new column.
:param col: a :class:`Column` expression for the new column.
>>> df.withColumn('age2', df.age + 2).collect()
[Row(age=2, name=u'Alice', age2=4), Row(age=5, name=u'Bob', age2=7)]
"""
return self.select('*', col.alias(colName))
@ignore_unicode_prefix
def withColumnRenamed(self, existing, new):
"""Returns a new :class:`DataFrame` by renaming an existing column.
:param existing: string, name of the existing column to rename.
:param col: string, new name of the column.
>>> df.withColumnRenamed('age', 'age2').collect()
[Row(age2=2, name=u'Alice'), Row(age2=5, name=u'Bob')]
"""
cols = [Column(_to_java_column(c)).alias(new)
if c == existing else c
for c in self.columns]
return self.select(*cols)
@ignore_unicode_prefix
def drop(self, colName):
"""Returns a new :class:`DataFrame` that drops the specified column.
:param colName: string, name of the column to drop.
>>> df.drop('age').collect()
[Row(name=u'Alice'), Row(name=u'Bob')]
"""
jdf = self._jdf.drop(colName)
return DataFrame(jdf, self.sql_ctx)
def toPandas(self):
"""Returns the contents of this :class:`DataFrame` as Pandas ``pandas.DataFrame``.
This is only available if Pandas is installed and available.
>>> df.toPandas() # doctest: +SKIP
age name
0 2 Alice
1 5 Bob
"""
import pandas as pd
return pd.DataFrame.from_records(self.collect(), columns=self.columns)
# Pandas compatibility
groupby = groupBy
drop_duplicates = dropDuplicates
# Having SchemaRDD for backward compatibility (for docs)
class SchemaRDD(DataFrame):
"""SchemaRDD is deprecated, please use :class:`DataFrame`.
"""
def dfapi(f):
def _api(self):
name = f.__name__
jdf = getattr(self._jdf, name)()
return DataFrame(jdf, self.sql_ctx)
_api.__name__ = f.__name__
_api.__doc__ = f.__doc__
return _api
def df_varargs_api(f):
def _api(self, *args):
name = f.__name__
jdf = getattr(self._jdf, name)(_to_seq(self.sql_ctx._sc, args))
return DataFrame(jdf, self.sql_ctx)
_api.__name__ = f.__name__
_api.__doc__ = f.__doc__
return _api
class GroupedData(object):
"""
A set of methods for aggregations on a :class:`DataFrame`,
created by :func:`DataFrame.groupBy`.
"""
def __init__(self, jdf, sql_ctx):
self._jdf = jdf
self.sql_ctx = sql_ctx
@ignore_unicode_prefix
def agg(self, *exprs):
"""Compute aggregates and returns the result as a :class:`DataFrame`.
The available aggregate functions are `avg`, `max`, `min`, `sum`, `count`.
If ``exprs`` is a single :class:`dict` mapping from string to string, then the key
is the column to perform aggregation on, and the value is the aggregate function.
Alternatively, ``exprs`` can also be a list of aggregate :class:`Column` expressions.
:param exprs: a dict mapping from column name (string) to aggregate functions (string),
or a list of :class:`Column`.
>>> gdf = df.groupBy(df.name)
>>> gdf.agg({"*": "count"}).collect()
[Row(name=u'Alice', COUNT(1)=1), Row(name=u'Bob', COUNT(1)=1)]
>>> from pyspark.sql import functions as F
>>> gdf.agg(F.min(df.age)).collect()
[Row(name=u'Alice', MIN(age)=2), Row(name=u'Bob', MIN(age)=5)]
"""
assert exprs, "exprs should not be empty"
if len(exprs) == 1 and isinstance(exprs[0], dict):
jdf = self._jdf.agg(exprs[0])
else:
# Columns
assert all(isinstance(c, Column) for c in exprs), "all exprs should be Column"
jdf = self._jdf.agg(exprs[0]._jc,
_to_seq(self.sql_ctx._sc, [c._jc for c in exprs[1:]]))
return DataFrame(jdf, self.sql_ctx)
@dfapi
def count(self):
"""Counts the number of records for each group.
>>> df.groupBy(df.age).count().collect()
[Row(age=2, count=1), Row(age=5, count=1)]
"""
@df_varargs_api
def mean(self, *cols):
"""Computes average values for each numeric columns for each group.
:func:`mean` is an alias for :func:`avg`.
:param cols: list of column names (string). Non-numeric columns are ignored.
>>> df.groupBy().mean('age').collect()
[Row(AVG(age)=3.5)]
>>> df3.groupBy().mean('age', 'height').collect()
[Row(AVG(age)=3.5, AVG(height)=82.5)]
"""
@df_varargs_api
def avg(self, *cols):
"""Computes average values for each numeric columns for each group.
:func:`mean` is an alias for :func:`avg`.
:param cols: list of column names (string). Non-numeric columns are ignored.
>>> df.groupBy().avg('age').collect()
[Row(AVG(age)=3.5)]
>>> df3.groupBy().avg('age', 'height').collect()
[Row(AVG(age)=3.5, AVG(height)=82.5)]
"""
@df_varargs_api
def max(self, *cols):
"""Computes the max value for each numeric columns for each group.
>>> df.groupBy().max('age').collect()
[Row(MAX(age)=5)]
>>> df3.groupBy().max('age', 'height').collect()
[Row(MAX(age)=5, MAX(height)=85)]
"""
@df_varargs_api
def min(self, *cols):
"""Computes the min value for each numeric column for each group.
:param cols: list of column names (string). Non-numeric columns are ignored.
>>> df.groupBy().min('age').collect()
[Row(MIN(age)=2)]
>>> df3.groupBy().min('age', 'height').collect()
[Row(MIN(age)=2, MIN(height)=80)]
"""
@df_varargs_api
def sum(self, *cols):
"""Compute the sum for each numeric columns for each group.
:param cols: list of column names (string). Non-numeric columns are ignored.
>>> df.groupBy().sum('age').collect()
[Row(SUM(age)=7)]
>>> df3.groupBy().sum('age', 'height').collect()
[Row(SUM(age)=7, SUM(height)=165)]
"""
def _create_column_from_literal(literal):
sc = SparkContext._active_spark_context
return sc._jvm.functions.lit(literal)
def _create_column_from_name(name):
sc = SparkContext._active_spark_context
return sc._jvm.functions.col(name)
def _to_java_column(col):
if isinstance(col, Column):
jcol = col._jc
else:
jcol = _create_column_from_name(col)
return jcol
def _to_seq(sc, cols, converter=None):
"""
Convert a list of Column (or names) into a JVM Seq of Column.
An optional `converter` could be used to convert items in `cols`
into JVM Column objects.
"""
if converter:
cols = [converter(c) for c in cols]
return sc._jvm.PythonUtils.toSeq(cols)
def _to_scala_map(sc, jm):
"""
Convert a dict into a JVM Map.
"""
return sc._jvm.PythonUtils.toScalaMap(jm)
def _unary_op(name, doc="unary operator"):
""" Create a method for given unary operator """
def _(self):
jc = getattr(self._jc, name)()
return Column(jc)
_.__doc__ = doc
return _
def _func_op(name, doc=''):
def _(self):
sc = SparkContext._active_spark_context
jc = getattr(sc._jvm.functions, name)(self._jc)
return Column(jc)
_.__doc__ = doc
return _
def _bin_op(name, doc="binary operator"):
""" Create a method for given binary operator
"""
def _(self, other):
jc = other._jc if isinstance(other, Column) else other
njc = getattr(self._jc, name)(jc)
return Column(njc)
_.__doc__ = doc
return _
def _reverse_op(name, doc="binary operator"):
""" Create a method for binary operator (this object is on right side)
"""
def _(self, other):
jother = _create_column_from_literal(other)
jc = getattr(jother, name)(self._jc)
return Column(jc)
_.__doc__ = doc
return _
class Column(object):
"""
A column in a DataFrame.
:class:`Column` instances can be created by::
# 1. Select a column out of a DataFrame
df.colName
df["colName"]
# 2. Create from an expression
df.colName + 1
1 / df.colName
"""
def __init__(self, jc):
self._jc = jc
# arithmetic operators
__neg__ = _func_op("negate")
__add__ = _bin_op("plus")
__sub__ = _bin_op("minus")
__mul__ = _bin_op("multiply")
__div__ = _bin_op("divide")
__truediv__ = _bin_op("divide")
__mod__ = _bin_op("mod")
__radd__ = _bin_op("plus")
__rsub__ = _reverse_op("minus")
__rmul__ = _bin_op("multiply")
__rdiv__ = _reverse_op("divide")
__rtruediv__ = _reverse_op("divide")
__rmod__ = _reverse_op("mod")
# logistic operators
__eq__ = _bin_op("equalTo")
__ne__ = _bin_op("notEqual")
__lt__ = _bin_op("lt")
__le__ = _bin_op("leq")
__ge__ = _bin_op("geq")
__gt__ = _bin_op("gt")
# `and`, `or`, `not` cannot be overloaded in Python,
# so use bitwise operators as boolean operators
__and__ = _bin_op('and')
__or__ = _bin_op('or')
__invert__ = _func_op('not')
__rand__ = _bin_op("and")
__ror__ = _bin_op("or")
# container operators
__contains__ = _bin_op("contains")
__getitem__ = _bin_op("apply")
# bitwise operators
bitwiseOR = _bin_op("bitwiseOR")
bitwiseAND = _bin_op("bitwiseAND")
bitwiseXOR = _bin_op("bitwiseXOR")
def getItem(self, key):
"""An expression that gets an item at position `ordinal` out of a list,
or gets an item by key out of a dict.
>>> df = sc.parallelize([([1, 2], {"key": "value"})]).toDF(["l", "d"])
>>> df.select(df.l.getItem(0), df.d.getItem("key")).show()
+----+------+
|l[0]|d[key]|
+----+------+
| 1| value|
+----+------+
>>> df.select(df.l[0], df.d["key"]).show()
+----+------+
|l[0]|d[key]|
+----+------+
| 1| value|
+----+------+
"""
return self[key]
def getField(self, name):
"""An expression that gets a field by name in a StructField.
>>> from pyspark.sql import Row
>>> df = sc.parallelize([Row(r=Row(a=1, b="b"))]).toDF()
>>> df.select(df.r.getField("b")).show()
+----+
|r[b]|
+----+
| b|
+----+
>>> df.select(df.r.a).show()
+----+
|r[a]|
+----+
| 1|
+----+
"""
return self[name]
def __getattr__(self, item):
if item.startswith("__"):
raise AttributeError(item)
return self.getField(item)
# string methods
rlike = _bin_op("rlike")
like = _bin_op("like")
startswith = _bin_op("startsWith")
endswith = _bin_op("endsWith")
@ignore_unicode_prefix
def substr(self, startPos, length):
"""
Return a :class:`Column` which is a substring of the column
:param startPos: start position (int or Column)
:param length: length of the substring (int or Column)
>>> df.select(df.name.substr(1, 3).alias("col")).collect()
[Row(col=u'Ali'), Row(col=u'Bob')]
"""
if type(startPos) != type(length):
raise TypeError("Can not mix the type")
if isinstance(startPos, (int, long)):
jc = self._jc.substr(startPos, length)
elif isinstance(startPos, Column):
jc = self._jc.substr(startPos._jc, length._jc)
else:
raise TypeError("Unexpected type: %s" % type(startPos))
return Column(jc)
__getslice__ = substr
@ignore_unicode_prefix
def inSet(self, *cols):
""" A boolean expression that is evaluated to true if the value of this
expression is contained by the evaluated values of the arguments.
>>> df[df.name.inSet("Bob", "Mike")].collect()
[Row(age=5, name=u'Bob')]
>>> df[df.age.inSet([1, 2, 3])].collect()
[Row(age=2, name=u'Alice')]
"""
if len(cols) == 1 and isinstance(cols[0], (list, set)):
cols = cols[0]
cols = [c._jc if isinstance(c, Column) else _create_column_from_literal(c) for c in cols]
sc = SparkContext._active_spark_context
jc = getattr(self._jc, "in")(_to_seq(sc, cols))
return Column(jc)
# order
asc = _unary_op("asc", "Returns a sort expression based on the"
" ascending order of the given column name.")
desc = _unary_op("desc", "Returns a sort expression based on the"
" descending order of the given column name.")
isNull = _unary_op("isNull", "True if the current expression is null.")
isNotNull = _unary_op("isNotNull", "True if the current expression is not null.")
def alias(self, alias):
"""Return a alias for this column
>>> df.select(df.age.alias("age2")).collect()
[Row(age2=2), Row(age2=5)]
"""
return Column(getattr(self._jc, "as")(alias))
@ignore_unicode_prefix
def cast(self, dataType):
""" Convert the column into type `dataType`
>>> df.select(df.age.cast("string").alias('ages')).collect()
[Row(ages=u'2'), Row(ages=u'5')]
>>> df.select(df.age.cast(StringType()).alias('ages')).collect()
[Row(ages=u'2'), Row(ages=u'5')]
"""
if isinstance(dataType, basestring):
jc = self._jc.cast(dataType)
elif isinstance(dataType, DataType):
sc = SparkContext._active_spark_context
ssql_ctx = sc._jvm.SQLContext(sc._jsc.sc())
jdt = ssql_ctx.parseDataType(dataType.json())
jc = self._jc.cast(jdt)
else:
raise TypeError("unexpected type: %s" % type(dataType))
return Column(jc)
@ignore_unicode_prefix
def between(self, lowerBound, upperBound):
""" A boolean expression that is evaluated to true if the value of this
expression is between the given columns.
"""
return (self >= lowerBound) & (self <= upperBound)
def __repr__(self):
return 'Column<%s>' % self._jc.toString().encode('utf8')
class DataFrameNaFunctions(object):
"""Functionality for working with missing data in :class:`DataFrame`.
"""
def __init__(self, df):
self.df = df
def drop(self, how='any', thresh=None, subset=None):
return self.df.dropna(how=how, thresh=thresh, subset=subset)
drop.__doc__ = DataFrame.dropna.__doc__
def fill(self, value, subset=None):
return self.df.fillna(value=value, subset=subset)
fill.__doc__ = DataFrame.fillna.__doc__
class DataFrameStatFunctions(object):
"""Functionality for statistic functions with :class:`DataFrame`.
"""
def __init__(self, df):
self.df = df
def corr(self, col1, col2, method=None):
return self.df.corr(col1, col2, method)
corr.__doc__ = DataFrame.corr.__doc__
def cov(self, col1, col2):
return self.df.cov(col1, col2)
cov.__doc__ = DataFrame.cov.__doc__
def crosstab(self, col1, col2):
return self.df.crosstab(col1, col2)
crosstab.__doc__ = DataFrame.crosstab.__doc__
def freqItems(self, cols, support=None):
return self.df.freqItems(cols, support)
freqItems.__doc__ = DataFrame.freqItems.__doc__
def _test():
import doctest
from pyspark.context import SparkContext
from pyspark.sql import Row, SQLContext
import pyspark.sql.dataframe
globs = pyspark.sql.dataframe.__dict__.copy()
sc = SparkContext('local[4]', 'PythonTest')
globs['sc'] = sc
globs['sqlContext'] = SQLContext(sc)
globs['df'] = sc.parallelize([(2, 'Alice'), (5, 'Bob')])\
.toDF(StructType([StructField('age', IntegerType()),
StructField('name', StringType())]))
globs['df2'] = sc.parallelize([Row(name='Tom', height=80), Row(name='Bob', height=85)]).toDF()
globs['df3'] = sc.parallelize([Row(name='Alice', age=2, height=80),
Row(name='Bob', age=5, height=85)]).toDF()
globs['df4'] = sc.parallelize([Row(name='Alice', age=10, height=80),
Row(name='Bob', age=5, height=None),
Row(name='Tom', age=None, height=None),
Row(name=None, age=None, height=None)]).toDF()
(failure_count, test_count) = doctest.testmod(
pyspark.sql.dataframe, globs=globs,
optionflags=doctest.ELLIPSIS | doctest.NORMALIZE_WHITESPACE | doctest.REPORT_NDIFF)
globs['sc'].stop()
if failure_count:
exit(-1)
if __name__ == "__main__":
_test()
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