d9978fb4e4
The docs describing RangeBetween & RowsBetween for pySpark & SparkR are not in sync with Spark description. a. Edited PySpark and SparkR docs and made description same for both RangeBetween and RowsBetween b. created executable examples in both pySpark and SparkR documentation c. Locally tested the patch for scala Style checks and UT for checking no testcase failures Closes #23946 from jagadesh-kiran/master. Authored-by: Jagadesh Kiran <jagadesh.n@in.verizon.com> Signed-off-by: Sean Owen <sean.owen@databricks.com>
301 lines
12 KiB
Python
301 lines
12 KiB
Python
#
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# Licensed to the Apache Software Foundation (ASF) under one or more
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# contributor license agreements. See the NOTICE file distributed with
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# this work for additional information regarding copyright ownership.
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# The ASF licenses this file to You under the Apache License, Version 2.0
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# (the "License"); you may not use this file except in compliance with
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# the License. You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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#
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import sys
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from pyspark import since, SparkContext
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from pyspark.sql.column import _to_seq, _to_java_column
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__all__ = ["Window", "WindowSpec"]
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def _to_java_cols(cols):
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sc = SparkContext._active_spark_context
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if len(cols) == 1 and isinstance(cols[0], list):
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cols = cols[0]
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return _to_seq(sc, cols, _to_java_column)
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class Window(object):
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"""
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Utility functions for defining window in DataFrames.
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For example:
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>>> # ORDER BY date ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW
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>>> window = Window.orderBy("date").rowsBetween(Window.unboundedPreceding, Window.currentRow)
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>>> # PARTITION BY country ORDER BY date RANGE BETWEEN 3 PRECEDING AND 3 FOLLOWING
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>>> window = Window.orderBy("date").partitionBy("country").rangeBetween(-3, 3)
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.. note:: When ordering is not defined, an unbounded window frame (rowFrame,
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unboundedPreceding, unboundedFollowing) is used by default. When ordering is defined,
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a growing window frame (rangeFrame, unboundedPreceding, currentRow) is used by default.
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.. note:: Experimental
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.. versionadded:: 1.4
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"""
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_JAVA_MIN_LONG = -(1 << 63) # -9223372036854775808
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_JAVA_MAX_LONG = (1 << 63) - 1 # 9223372036854775807
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_PRECEDING_THRESHOLD = max(-sys.maxsize, _JAVA_MIN_LONG)
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_FOLLOWING_THRESHOLD = min(sys.maxsize, _JAVA_MAX_LONG)
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unboundedPreceding = _JAVA_MIN_LONG
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unboundedFollowing = _JAVA_MAX_LONG
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currentRow = 0
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@staticmethod
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@since(1.4)
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def partitionBy(*cols):
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"""
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Creates a :class:`WindowSpec` with the partitioning defined.
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"""
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sc = SparkContext._active_spark_context
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jspec = sc._jvm.org.apache.spark.sql.expressions.Window.partitionBy(_to_java_cols(cols))
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return WindowSpec(jspec)
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@staticmethod
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@since(1.4)
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def orderBy(*cols):
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"""
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Creates a :class:`WindowSpec` with the ordering defined.
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"""
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sc = SparkContext._active_spark_context
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jspec = sc._jvm.org.apache.spark.sql.expressions.Window.orderBy(_to_java_cols(cols))
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return WindowSpec(jspec)
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@staticmethod
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@since(2.1)
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def rowsBetween(start, end):
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"""
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Creates a :class:`WindowSpec` with the frame boundaries defined,
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from `start` (inclusive) to `end` (inclusive).
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Both `start` and `end` are relative positions from the current row.
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For example, "0" means "current row", while "-1" means the row before
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the current row, and "5" means the fifth row after the current row.
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We recommend users use ``Window.unboundedPreceding``, ``Window.unboundedFollowing``,
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and ``Window.currentRow`` to specify special boundary values, rather than using integral
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values directly.
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A row based boundary is based on the position of the row within the partition.
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An offset indicates the number of rows above or below the current row, the frame for the
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current row starts or ends. For instance, given a row based sliding frame with a lower bound
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offset of -1 and a upper bound offset of +2. The frame for row with index 5 would range from
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index 4 to index 6.
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>>> from pyspark.sql import Window
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>>> from pyspark.sql import functions as func
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>>> from pyspark.sql import SQLContext
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>>> sc = SparkContext.getOrCreate()
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>>> sqlContext = SQLContext(sc)
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>>> tup = [(1, "a"), (1, "a"), (2, "a"), (1, "b"), (2, "b"), (3, "b")]
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>>> df = sqlContext.createDataFrame(tup, ["id", "category"])
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>>> window = Window.partitionBy("category").orderBy("id").rowsBetween(Window.currentRow, 1)
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>>> df.withColumn("sum", func.sum("id").over(window)).show()
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+---+--------+---+
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| id|category|sum|
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+---+--------+---+
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| 1| b| 3|
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| 2| b| 5|
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| 3| b| 3|
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| 1| a| 2|
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| 1| a| 3|
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| 2| a| 2|
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+---+--------+---+
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:param start: boundary start, inclusive.
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The frame is unbounded if this is ``Window.unboundedPreceding``, or
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any value less than or equal to -9223372036854775808.
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:param end: boundary end, inclusive.
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The frame is unbounded if this is ``Window.unboundedFollowing``, or
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any value greater than or equal to 9223372036854775807.
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"""
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if start <= Window._PRECEDING_THRESHOLD:
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start = Window.unboundedPreceding
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if end >= Window._FOLLOWING_THRESHOLD:
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end = Window.unboundedFollowing
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sc = SparkContext._active_spark_context
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jspec = sc._jvm.org.apache.spark.sql.expressions.Window.rowsBetween(start, end)
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return WindowSpec(jspec)
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@staticmethod
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@since(2.1)
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def rangeBetween(start, end):
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"""
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Creates a :class:`WindowSpec` with the frame boundaries defined,
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from `start` (inclusive) to `end` (inclusive).
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Both `start` and `end` are relative from the current row. For example,
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"0" means "current row", while "-1" means one off before the current row,
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and "5" means the five off after the current row.
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We recommend users use ``Window.unboundedPreceding``, ``Window.unboundedFollowing``,
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and ``Window.currentRow`` to specify special boundary values, rather than using integral
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values directly.
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A range-based boundary is based on the actual value of the ORDER BY
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expression(s). An offset is used to alter the value of the ORDER BY expression, for
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instance if the current ORDER BY expression has a value of 10 and the lower bound offset
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is -3, the resulting lower bound for the current row will be 10 - 3 = 7. This however puts a
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number of constraints on the ORDER BY expressions: there can be only one expression and this
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expression must have a numerical data type. An exception can be made when the offset is
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unbounded, because no value modification is needed, in this case multiple and non-numeric
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ORDER BY expression are allowed.
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>>> from pyspark.sql import Window
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>>> from pyspark.sql import functions as func
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>>> from pyspark.sql import SQLContext
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>>> sc = SparkContext.getOrCreate()
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>>> sqlContext = SQLContext(sc)
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>>> tup = [(1, "a"), (1, "a"), (2, "a"), (1, "b"), (2, "b"), (3, "b")]
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>>> df = sqlContext.createDataFrame(tup, ["id", "category"])
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>>> window = Window.partitionBy("category").orderBy("id").rangeBetween(Window.currentRow, 1)
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>>> df.withColumn("sum", func.sum("id").over(window)).show()
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+---+--------+---+
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| id|category|sum|
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+---+--------+---+
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| 1| b| 3|
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| 2| b| 5|
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| 3| b| 3|
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| 1| a| 4|
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| 1| a| 4|
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| 2| a| 2|
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+---+--------+---+
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:param start: boundary start, inclusive.
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The frame is unbounded if this is ``Window.unboundedPreceding``, or
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any value less than or equal to max(-sys.maxsize, -9223372036854775808).
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:param end: boundary end, inclusive.
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The frame is unbounded if this is ``Window.unboundedFollowing``, or
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any value greater than or equal to min(sys.maxsize, 9223372036854775807).
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"""
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if start <= Window._PRECEDING_THRESHOLD:
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start = Window.unboundedPreceding
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if end >= Window._FOLLOWING_THRESHOLD:
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end = Window.unboundedFollowing
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sc = SparkContext._active_spark_context
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jspec = sc._jvm.org.apache.spark.sql.expressions.Window.rangeBetween(start, end)
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return WindowSpec(jspec)
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class WindowSpec(object):
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"""
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A window specification that defines the partitioning, ordering,
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and frame boundaries.
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Use the static methods in :class:`Window` to create a :class:`WindowSpec`.
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.. note:: Experimental
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.. versionadded:: 1.4
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"""
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def __init__(self, jspec):
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self._jspec = jspec
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@since(1.4)
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def partitionBy(self, *cols):
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"""
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Defines the partitioning columns in a :class:`WindowSpec`.
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:param cols: names of columns or expressions
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"""
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return WindowSpec(self._jspec.partitionBy(_to_java_cols(cols)))
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@since(1.4)
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def orderBy(self, *cols):
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"""
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Defines the ordering columns in a :class:`WindowSpec`.
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:param cols: names of columns or expressions
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"""
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return WindowSpec(self._jspec.orderBy(_to_java_cols(cols)))
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@since(1.4)
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def rowsBetween(self, start, end):
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"""
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Defines the frame boundaries, from `start` (inclusive) to `end` (inclusive).
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Both `start` and `end` are relative positions from the current row.
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For example, "0" means "current row", while "-1" means the row before
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the current row, and "5" means the fifth row after the current row.
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We recommend users use ``Window.unboundedPreceding``, ``Window.unboundedFollowing``,
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and ``Window.currentRow`` to specify special boundary values, rather than using integral
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values directly.
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:param start: boundary start, inclusive.
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The frame is unbounded if this is ``Window.unboundedPreceding``, or
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any value less than or equal to max(-sys.maxsize, -9223372036854775808).
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:param end: boundary end, inclusive.
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The frame is unbounded if this is ``Window.unboundedFollowing``, or
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any value greater than or equal to min(sys.maxsize, 9223372036854775807).
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"""
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if start <= Window._PRECEDING_THRESHOLD:
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start = Window.unboundedPreceding
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if end >= Window._FOLLOWING_THRESHOLD:
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end = Window.unboundedFollowing
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return WindowSpec(self._jspec.rowsBetween(start, end))
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@since(1.4)
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def rangeBetween(self, start, end):
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"""
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Defines the frame boundaries, from `start` (inclusive) to `end` (inclusive).
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Both `start` and `end` are relative from the current row. For example,
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"0" means "current row", while "-1" means one off before the current row,
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and "5" means the five off after the current row.
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We recommend users use ``Window.unboundedPreceding``, ``Window.unboundedFollowing``,
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and ``Window.currentRow`` to specify special boundary values, rather than using integral
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values directly.
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:param start: boundary start, inclusive.
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The frame is unbounded if this is ``Window.unboundedPreceding``, or
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any value less than or equal to max(-sys.maxsize, -9223372036854775808).
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:param end: boundary end, inclusive.
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The frame is unbounded if this is ``Window.unboundedFollowing``, or
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any value greater than or equal to min(sys.maxsize, 9223372036854775807).
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"""
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if start <= Window._PRECEDING_THRESHOLD:
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start = Window.unboundedPreceding
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if end >= Window._FOLLOWING_THRESHOLD:
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end = Window.unboundedFollowing
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return WindowSpec(self._jspec.rangeBetween(start, end))
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def _test():
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import doctest
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import pyspark.sql.window
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SparkContext('local[4]', 'PythonTest')
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globs = pyspark.sql.window.__dict__.copy()
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(failure_count, test_count) = doctest.testmod(
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pyspark.sql.window, globs=globs,
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optionflags=doctest.NORMALIZE_WHITESPACE)
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if failure_count:
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sys.exit(-1)
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if __name__ == "__main__":
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_test()
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