when

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

Syntax

from pyspark.sql import functions as dbf

dbf.when(condition=<condition>, value=<value>)

Parameters

Parameter	Type	Description
condition	pyspark.sql.Column	A boolean Column expression.
value	Any	A literal value, or a Column expression.

Returns

pyspark.sql.Column: column representing when expression.

Examples

from pyspark.sql import functions as dbf
df = spark.range(3)
df.select("*", dbf.when(df['id'] == 2, 3).otherwise(4)).show()

+---+------------------------------------+
| id|CASE WHEN (id = 2) THEN 3 ELSE 4 END|
+---+------------------------------------+
|  0|                                   4|
|  1|                                   4|
|  2|                                   3|
+---+------------------------------------+