pyspark.sql.functions.when¶
- 
pyspark.sql.functions.when(condition: pyspark.sql.column.Column, value: Any) → pyspark.sql.column.Column[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
- 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| +----+