Rename column by index in Pandas

Last Updated : 26 Dec, 2020

Prerequisites: Pandas

A column of a data frame can be changed using the position it is in known as its index. Just by the use of index a column can be renamed. This article discusses all such possible methods.

Approach:

Import required python library.
Create data
Provide index of the column to be renamed as argument to rename() function.

Pandas rename() method is used to rename any index, column or row.

Syntax: rename(mapper=None, index=None, columns=None, axis=None, copy=True, inplace=False, level=None)

Parameters:

mapper, index and columns: Dictionary value, key refers to the old name and value refers to new name. Only one of these parameters can be used at once.

axis: int or string value, 0/’row’ for Rows and 1/’columns’ for Columns

copy: Copies underlying data if True.

inplace: Makes changes in original Data Frame if True.

level: Used to specify level in case data frame is having multiple level index.

Return Type: Data frame with new names

Given below are various implementation to achieve our required functionality:

Example 1: Switching both column names with each other using column index.

Python3

import pandas as pd 
  
# Sample DataFrame 
df = pd.DataFrame({'a': [1, 2], 'b': [3, 4]}) 
  
# Changing columns name with index number 
df.columns.values[0] = "b"
df.columns.values[1] = "a"
  
# Display 
display(df) 

Output:

Example 2: Using another method to rename the column with index.

Python3

import pandas as pd 
  
# Sample DataFrame 
df = pd.DataFrame({'a': [1, 2], 'b': [3, 4]}) 
  
# Changing columns name with index number 
su = df.rename(columns={df.columns[1]: 'new'}) 
  
# Display 
display(su) 

Output:

Example 3: Renaming two/more columns in a single command using an index number.

Python3

import pandas as pd 
  
# Sample DataFrame 
df = pd.DataFrame({'a': [1, 2], 'b': [3, 4], 'c': [7, 8]}) 
  
# Changing columns name with index number 
mapping = {df.columns[0]: 'new0', df.columns[1]: 'new1'} 
su = df.rename(columns=mapping) 
  
# Display 
display(su) 

Output:

Example 4: Renaming column name with an index number of the CSV file.

File in use: Data1.csv

Link: Click here

Python3

import pandas as pd 
  
# reading a csv file 
df1 = pd.read_csv("data1.csv") 
  
# change 2nd column name with index number 
df1.columns.values[2] = "city"
  
# Display DataFrame 
display(df1) 