如何在Pyspark中根据另一列的值选择另一列？

from pyspark.sql import SparkSession
from pyspark.sql.functions import col, when

spark = SparkSession.builder.getOrCreate()

data = [("Alice", 25, "F"), ("Bob", 30, "M"), ("Charlie", 35, "M")]
df = spark.createDataFrame(data, ["name", "age", "gender"])
df.show()

+-------+---+------+
|   name|age|gender|
+-------+---+------+
|  Alice| 25|     F|
|    Bob| 30|     M|
|Charlie| 35|     M|
+-------+---+------+

df.select("name", "age", "gender", when(col("gender") == "M", col("age")).otherwise(None).alias("selected_age")).show()

+-------+---+------+------------+
|   name|age|gender|selected_age|
+-------+---+------+------------+
|  Alice| 25|     F|        null|
|    Bob| 30|     M|          30|
|Charlie| 35|     M|          35|
+-------+---+------+------------+