如何枚举Spark的DataFrame中的列？如果列是嵌套的呢？

from pyspark.sql import SparkSession

# 创建SparkSession
spark = SparkSession.builder.getOrCreate()

# 读取数据并创建DataFrame
df = spark.read.csv("data.csv", header=True, inferSchema=True)

# 枚举DataFrame中的列
columns = df.columns
print(columns)

from pyspark.sql import SparkSession

# 创建SparkSession
spark = SparkSession.builder.getOrCreate()

# 读取数据并创建DataFrame
df = spark.read.json("data.json")

# 选择嵌套列并为列指定别名
df = df.select("nested.column1.alias1", "nested.column2.alias2")

# 枚举嵌套列的别名
columns = df.columns
print(columns)