CODEWITHSUNDEEP
pythonpandas
armin
armin

Reputation: 651

Changing multiple column names by column number in Pandas?

I am borrowing this example from here. I have a dataframe like this:

# Import pandas package 
import pandas as pd 
   
# Define a dictionary containing ICC rankings 
rankings = {'test': ['India', 'South Africa', 'England', 
                            'New Zealand', 'Australia'], 
              'odi': ['England', 'India', 'New Zealand', 
                            'South Africa', 'Pakistan'], 
               't20': ['Pakistan', 'India', 'Australia', 
                              'England', 'New Zealand']} 
   
# Convert the dictionary into DataFrame 
rankings_pd = pd.DataFrame(rankings) 
   
# Before renaming the columns 
print(rankings_pd)
          test           odi          t20
0         India       England     Pakistan
1  South Africa         India        India
2       England   New Zealand    Australia
3   New Zealand  South Africa      England
4     Australia      Pakistan  New Zealand

Now let's say I want to change the name of the 1st and 2nd columns. This is what I am trying:

rankings_pd[rankings_pd.columns[0:2]].columns =  ['tes_after_change', 'odi_after_change']
print(rankings_pd[rankings_pd.columns[0:2]].columns)
Index(['test', 'odi'], dtype='object')

But this seems to return exactly the same columns names and not changing them.

Upvotes: 3

Views: 198

Answers (3)

Anurag Dabas
Anurag Dabas

Reputation: 24304

Just use rename() method and pass the dictionary of old values and new values as key-value pair in columns parameter:-

rankings_pd=rankings_pd.rename(columns={'test':'tes_after_change','odi':'odi_after_change'})

Edit by @sammywemmy:

You could extend the idea with an anonymous function :

rankings_pd.rename(columns= lambda df: f"{df}_after_change" if df in ("test", "odi") else df)

Upvotes: 8

anky
anky

Reputation: 75080

You can use to_numpy() and replace the slice:

rankings_pd.columns.to_numpy()[0:2] = ['tes_after_change', 'odi_after_change']

rankings_pd.columns
#Index(['tes_after_change', 'odi_after_change', 't20'], dtype='object')

Or using np.r_ with df.rename

rankings_pd.rename(dict(zip(rankings_pd.columns[np.r_[0:2]],
                        ['tes_after_change', 'odi_after_change'])),axis=1)

Upvotes: 4

Quang Hoang
Quang Hoang

Reputation: 150735

You should/could not replace part of the columns. You need to replace them all at once:

rankings_pd.columns = ['tes_after_change', 'odi_after_change'] + rankings_pd.columns[2:].tolist()

Upvotes: 4

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