CODEWITHSUNDEEP
pythonpandas
TayyabRahmani
TayyabRahmani

Reputation: 123

Add a column for category after groupby

I would like to groupby and get the another column containing category of groupby: This is my input

x=pd.DataFrame({'A': ['a', 'b', 'a', 'c'], 'B': ['w', 'x', 'w', 'y']})

I expect this to be the output:

y=pd.DataFrame({'A': ['a', 'b', 'a', 'c'], 'B': ['w', 'x', 'w', 'y'], 'C': ['C0', 'C1', 'C0', 'C2']})

I have tried this:

'C' + nlp.groupby(['HCCTrack (S)', 'AdditionalCodes (S)']).cumcount().add(1).astype(str)

Upvotes: 0

Views: 22

Answers (1)

jezrael
jezrael

Reputation: 863196

Use GroupBy.ngroup instead GroupBy.cumcount:

x['C'] = 'C' + x.groupby(['A', 'B']).ngroup().astype(str)
print (x)
   A  B   C
0  a  w  C0
1  b  x  C1
2  a  w  C0
3  c  y  C2

Upvotes: 1

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