pyspark.sql.functions.when#

pyspark.sql.functions.when(condition, value)[source]#

Evaluates a list of conditions and returns one of multiple possible result expressions. If pyspark.sql.Column.otherwise() is not invoked, None is returned for unmatched conditions.

New in version 1.4.0.

Changed in version 3.4.0: Supports Spark Connect.

Parameters

conditionColumn: a boolean Column expression.
value: a literal value, or a Column expression.

Returns

Column: column representing when expression.

Examples

>>> df = spark.range(3)
>>> df.select(when(df['id'] == 2, 3).otherwise(4).alias("age")).show()
+---+
|age|
+---+
|  4|
|  4|
|  3|
+---+

>>> df.select(when(df.id == 2, df.id + 1).alias("age")).show()
+----+
| age|
+----+
|NULL|
|NULL|
|   3|
+----+