在 Spark 中,文字列在添加时不可为空:
from pyspark.sql import SparkSession,functions as F
spark = SparkSession.builder.getOrCreate()
df = spark.createDataFrame([(1,)],['c1'])
df = df.withColumn('c2',F.lit('a'))
df.printSchema()
# root
# |-- c1: long (nullable = true)
# |-- c2: string (nullable = false)
如何创建可为空的列?