如何重命名多个 PySpark DataFrame 列

在本文中，我们将讨论如何重命名 PySpark Dataframe 中的多列。为此，我们将使用withColumnRenamed()和toDF()函数。

创建用于演示的数据框：

Python3

# importing module
import pyspark
  
# importing sparksession from pyspark.sql module
from pyspark.sql import SparkSession
  
# creating sparksession and giving an app name
spark = SparkSession.builder.appName('sparkdf').getOrCreate()
  
# list  of students  data  with null values
# we can define null values with none
data = [[None, "sravan", "vignan"],
        ["2", None, "vvit"],
        ["3", "rohith", None],
        ["4", "sridevi", "vignan"],
        ["1", None, None],
        ["5", "gnanesh", "iit"]]
  
# specify column names
columns = ['ID', 'NAME', 'college']
  
# creating a dataframe from the lists of data
dataframe = spark.createDataFrame(data, columns)
  
# show columns
print(dataframe.columns)
  
# display dataframe
dataframe.show()

输出：

方法 1：使用 withColumnRenamed()

此方法用于重命名数据框中的列

Syntax: dataframe.withColumnRenamed(“old_column_name”, “new_column_name”)

where

• dataframe is the pyspark dataframe
• old_column_name is the existing column name
• new_column_name is the new column name

要更改多列，我们可以指定 n 次函数，用“.”分隔。运算符

Syntax: dataframe.withColumnRenamed(“old_column_name”, “new_column_name”).

withColumnRenamed”old_column_name”, “new_column_name”)

示例 1：更改两列的列名的Python程序

蟒蛇3

# display actual columns
print("Actual columns: ", dataframe.columns)
  
# change the college column name to university 
# and ID to student_id
dataframe = dataframe.withColumnRenamed(
  "college", "university").withColumnRenamed("ID", "student_id")
  
# display modified columns
print("modified columns: ", dataframe.columns)
  
# final dataframe
dataframe.show()

输出：

示例 2：重命名所有列

蟒蛇3

# display actual columns
print("Actual columns: ", dataframe.columns)
  
# change the college column name to university 
# and ID to student_id
dataframe = dataframe.withColumnRenamed(
  "college", "university").withColumnRenamed(
  "ID", "student_id").withColumnRenamed("NAME", "student_name")
  
# display modified columns
print("modified columns: ", dataframe.columns)
  
# final dataframe
dataframe.show()

输出：

方法 2：使用 toDF()

此方法用于更改数据框所有列的名称

Syntax: dataframe.toDF(*(“column 1″,”column 2”,”column n))

where, columns are the columns in the dataframe

示例：更改列名的Python程序

蟒蛇3

# display actual
print("Actual columns: ", dataframe.columns)
  
# change column names to A,B,C
dataframe = dataframe.toDF(*("A", "B", "C"))
  
# display new columns
print("New columns: ", dataframe.columns)
  
# display dataframe
dataframe.show()

输出：