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
Python
from pyspark.sql import functions as dbf
dbf.when(condition=<condition>, value=<value>)
Parameters
Parameter | Type | Description |
|---|---|---|
|
| A boolean Column expression. |
| Any | A literal value, or a Column expression. |
Returns
pyspark.sql.Column: column representing when expression.
Examples
Python
from pyspark.sql import functions as dbf
df = spark.range(3)
df.select("*", dbf.when(df['id'] == 2, 3).otherwise(4)).show()
Output
+---+------------------------------------+
| id|CASE WHEN (id = 2) THEN 3 ELSE 4 END|
+---+------------------------------------+
| 0| 4|
| 1| 4|
| 2| 3|
+---+------------------------------------+