How to sort pandas dataframe by custom order on string index

问题

I have the following data frame:

import pandas as pd

# Create DataFrame
df = pd.DataFrame(
{'id':[2967, 5335, 13950, 6141, 6169],\
 'Player': ['Cedric Hunter', 'Maurice Baker' ,\
            'Ratko Varda' ,'Ryan Bowen' ,'Adrian Caldwell'],\
 'Year': [1991 ,2004 ,2001 ,2009 ,1997],\
 'Age': [27 ,25 ,22 ,34 ,31],\
 'Tm':['CHH' ,'VAN' ,'TOT' ,'OKC' ,'DAL'],\
 'G':[6 ,7 ,60 ,52 ,81]})


df.set_index('Player', inplace=True)

It shows:

Out[128]:

                 Age   G   Tm  Year     id
Player
Cedric Hunter     27   6  CHH  1991   2967
Maurice Baker     25   7  VAN  2004   5335
Ratko Varda       22  60  TOT  2001  13950
Ryan Bowen        34  52  OKC  2009   6141
Adrian Caldwell   31  81  DAL  1997   6169

What I want to do is to sort the 'Player' index in the arbitrary order according to this list (NOTE: not alphabetical order):

reorderlist = [ 'Maurice Baker', 'Adrian Caldwell','Ratko Varda' ,'Ryan Bowen' ,'Cedric Hunter']

How can I do that?

回答1:

Just reindex

df.reindex(reorderlist)
Out[89]: 
                 Age   G   Tm  Year     id
Player                                    
Maurice Baker     25   7  VAN  2004   5335
Adrian Caldwell   31  81  DAL  1997   6169
Ratko Varda       22  60  TOT  2001  13950
Ryan Bowen        34  52  OKC  2009   6141
Cedric Hunter     27   6  CHH  1991   2967

回答2:

To get a custom sort-order on your list of strings, declare it as a categorical and manually specify that order in a sort:

player_order = pd.Categorical([ 'Maurice Baker', 'Adrian Caldwell','Ratko Varda' ,'Ryan Bowen' ,'Cedric Hunter'],
              ordered=True)

This is since pandas does not yet allow Categoricals as indices: df.set_index(keys=player_order, inplace=True) TypeError: unhashable type: 'Categorical'

So you'll want to do a manual custom sort using df.sort_index(level=player_order)

来源：https://stackoverflow.com/questions/50012525/how-to-sort-pandas-dataframe-by-custom-order-on-string-index

标签

python

pandas

sorting

indexing

categorical-data