CODEWITHSUNDEEP
pythonloopspandasdataframeindexing
Christopher Goings
Christopher Goings

Reputation: 159

Sum column of a hierarchical index?

The DataFrame without sum for column of a hierarchical index:

  dex1 dex2 dex3 one  two 
    H   D   A    1    2     
            B    4    5     
            C    7    8    
    I   E   A    1    1     
            B    2    2      
            C    3    3

The DataFrame with sum for a column of a hierarchical index should be, for columns df['one'] index dex1, 12 (1 + 4 + 7), 6 (1 + 2 + 3) and for column df['two'] of index dex1, 12 (1 + 4 + 7), 6 (1 + 2 + 3).

So far, I have tried:

df.loc[dex1].sum['one']

Upvotes: 2

Views: 588

Answers (1)

jezrael
jezrael

Reputation: 862761

You can use groupby + GroupBy.sum:

df1 = df.groupby(level='dex1').sum()
print (df1)
      one  two
dex1          
H      12   15
I       6    6

From version of pandas 0.20.0 is possible omit level parameter.

df1 = df.groupby('dex1').sum()
print (df1)
      one  two
dex1          
H      12   15
I       6    6

Or use DataFrame.sum with parameter level:

df1 = df.sum(level=0)
print (df1)
      one  two
dex1          
H      12   15
I       6    6

df1 = df.sum(level='dex1')
print (df1)
      one  two
dex1          
H      12   15
I       6    6

Upvotes: 2

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