last_value

Returns the last value of col for a group of rows. 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.

Syntax

from pyspark.sql import functions as sf

sf.last_value(col, ignoreNulls=None)

Parameters

Parameter	Type	Description
col	pyspark.sql.Column or str	Target column to work on.
ignoreNulls	pyspark.sql.Column or bool, optional	If first value is null then look for first non-null value.

Returns

pyspark.sql.Column: some value of col for a group of rows.

Examples

Example 1: Get last value without ignoring nulls

from pyspark.sql import functions as sf
spark.createDataFrame(
    [("a", 1), ("a", 2), ("a", 3), ("b", 8), (None, 2)], ["a", "b"]
).select(sf.last_value('a'), sf.last_value('b')).show()

+-------------+-------------+
|last_value(a)|last_value(b)|
+-------------+-------------+
|         NULL|            2|
+-------------+-------------+

Example 2: Get last value ignoring nulls

from pyspark.sql import functions as sf
spark.createDataFrame(
    [("a", 1), ("a", 2), ("a", 3), ("b", 8), (None, 2)], ["a", "b"]
).select(sf.last_value('a', True), sf.last_value('b', True)).show()

+-------------+-------------+
|last_value(a)|last_value(b)|
+-------------+-------------+
|            b|            2|
+-------------+-------------+