last

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. The function is non-deterministic because its results depends on the order of the rows which may be non-deterministic after a shuffle.

Syntax

from pyspark.sql import functions as sf

sf.last(col, ignorenulls=False)

Parameters

Parameter	Type	Description
col	pyspark.sql.Column or column name	Column to fetch last value for.
ignorenulls	bool	If last value is null then look for non-null value. False by default.

Returns

pyspark.sql.Column: last value of the group.

Examples

from pyspark.sql import functions as sf
df = spark.createDataFrame([("Alice", 2), ("Bob", 5), ("Alice", None)], ("name", "age"))
df = df.orderBy(df.age.desc())
df.groupby("name").agg(sf.last("age")).orderBy("name").show()

+-----+---------+
| name|last(age)|
+-----+---------+
|Alice|     NULL|
|  Bob|        5|
+-----+---------+

To ignore any null values, set ignorenulls to True:

df.groupby("name").agg(sf.last("age", ignorenulls=True)).orderBy("name").show()

+-----+---------+
| name|last(age)|
+-----+---------+
|Alice|        2|
|  Bob|        5|
+-----+---------+