CODEWITHSUNDEEP
pythonpandasdataframe
JamesHudson81
JamesHudson81

Reputation: 2273

Adding certain columns from dataframe

I have the following dataframe df:

    A  B  C  D  E

J   4  2  3  2  3
K   5  2  6  2  1
L   2  6  5  4  7

I would like to create an additional column that adds by index the df except column A (which also are numbers), therefore what I have tried is :

df['summation'] = df.iloc[:, 1:4].sum(axis=0)

However, the column summation is added but gives NaN values.

Desired output is: 

    A  B  C  D  E  summation

J   4  2  3  2  3    10
K   5  2  6  2  1    11
L   2  6  5  4  7    22

The sum along the row starting at B to the end.

Upvotes: 1

Views: 66

Answers (1)

Cleb
Cleb

Reputation: 26069

As pointed out in the comments, you apply sum on the wrong axis. If you want to exclude columns from the sum, you can use drop (which also accepts a list of column names which might be handy if you want to exclude columns at e.g. index 0 and 3; then iloc might not be ideal)

df.drop('A', axis=1).sum(axis=1)

which yields

J    10
K    11
L    22

Also @ayhan's solution in the comments works fine.

Upvotes: 1

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