如何用PySpark中某列的第一个非空值填充该列的空值

from pyspark.sql import SparkSession
from pyspark.sql.functions import col, first
from pyspark.sql.window import Window

spark = SparkSession.builder.getOrCreate()

df = spark.read.format("csv").option("header", "true").load("your_file.csv")

window = Window.orderBy("your_column")
df = df.withColumn("your_column", first(col("your_column"), ignorenulls=True).over(window))
df = df.fillna({"your_column": "your_default_value"})

df.show()