Pandas Mass Renaming Columns

I have a excel file which has a dates as column headers. The dates span to about 100 columns. I want to rename all these dates as Month1, Month2 and so forth. i am new to Pandas

Solution 1:

IIUC, we can create a dictionary using pd.to_datetime to get the Month Number.

I've used a psuedo list but you'll need to amend the

format='%B_%Y') to format='%b_%Y')

or whatever format your column name is.

setup

import pandas as pd
import numpy as np
import calendar

year_cols = ['colA','colB'] + [f"{c}_{i}"for i inrange(2020,2028) for c in calendar.month_name[1:]] 

nums = np.random.randint(0,500,size=len(year_cols))

df = pd.DataFrame([nums],columns=year_cols)

---

print(df.iloc[:,:7]) # print 7columns

   colA  colB  January_2020  February_2020  March_2020  April_2020  May_2020
0168296288298420172199

Create a dictionary.

rename_dict = {i : f"Month{pd.to_datetime(i,format='%B_%Y').strftime('%m')}"for i in df.iloc[:,2:].columns}

---

for k,v in rename_dict.items():
    if v == 'Month01':
        print(f'{k} -- > {v}')

January_2020 -- > Month01
January_2021 -- > Month01
January_2022 -- > Month01
January_2023 -- > Month01
January_2024 -- > Month01
January_2025 -- > Month01
January_2026 -- > Month01
January_2027 -- > Month01

---

rename columns.

df = df.rename(columns=rename_dict)

---

print(df.iloc[:,:7]) # print 7columns




   colA  colB  Month01  Month02  Month03  Month04  Month05
016829628829842017219