I would like to relocate columns by condition. In case country is 'Japan', I need to relocate last_name and first_name reverse.

df = pd.DataFrame([['France','Kylian', 'Mbappe'],['Japan','Hiroyuki', 'Tajima'],['Japan','Shiji', 'Kagawa'],['England','Harry', 'Kane'],['Japan','Yuya', 'Ohsako'],['Portuguese','Cristiano', 'Ronaldo']],columns=['country', 'first_name', 'last_name'])

Current output is

      country first_name last_name
0      France     Kylian    Mbappe
1       Japan   Hiroyuki    Tajima
2       Japan      Shiji    kagawa
3     England      Harry      Kane
4       Japan       Yuya    Ohsako
5  Portuguese  Cristiano   Ronaldo

I would like to make it following.

      country first_name last_name
0      France     Kylian    Mbappe
1       Japan     Tajima  Hiroyuki
2       Japan     Kagawa    Shinji
3     England      Harry      Kane
4       Japan     Ohsako      Yuya
5  Portuguese  Cristiano   Ronaldo

Any idea?

Use loc and swap the "first_name" and "last_name" values for rows whose "country" matches "Japan".

m = df['country'] == 'Japan'df.loc[m, ['first_name', 'last_name']] = (df.loc[m, ['last_name', 'first_name']].values)
df    country first_name last_name
0  France      Kylian     Mbappe  
1  Japan       Tajima     Hiroyuki
2  Japan       Kagawa     Shiji   
3  England     Harry      Kane    
4  Japan       Ohsako     Yuya    
5  Portuguese  Cristiano  Ronaldo 

Another option using rename and update:

mp = {'first_name': 'last_name', 'last_name': 'first_name'}
df.update(df.loc[m].rename(mp, axis=1))
dfcountry first_name last_name
0  France      Kylian     Mbappe  
1  Japan       Tajima     Hiroyuki
2  Japan       Kagawa     Shiji   
3  England     Harry      Kane    
4  Japan       Ohsako     Yuya    
5  Portuguese  Cristiano  Ronaldo