First column non-zero

Asked Feb 14 '19 at 20:08

Active Feb 14 '19 at 20:58

Viewed 51 times

I have the following python pandas data frame:

df = pd.DataFrame({'a':[0,2,0,0], 'b':[0,1,2,0], 'c':[1,1,5,8]})

I would like to have another column storing the name of the first columns non-zero

   a  b  c  result    
0  0  0  1  c
1  2  1  1  a
2  0  2  5  b
3  0  0  8  c

edited Feb 14 '19 at 20:14

asked Feb 14 '19 at 20:08

Gregor D

3

Use `df.idxmax(axis=1)` – cs95 Feb 14 '19 at 20:09
However, what if a row has [0, 1, 2]? Should it return b (first non-zero) or c (largest number)? – cs95 Feb 14 '19 at 20:10
It should return first non-zero – Gregor D Feb 14 '19 at 20:17
2

`df.ne(0).idxmax(1) ` – BENY Feb 14 '19 at 20:20
@Wen-Ben I have reopened, so you can write an answer :) – cs95 Feb 14 '19 at 20:21
I am not sure what is your intention, but if you want to have another column that says if the first column is zero or not you can do this: df['non-zero'] = df [df['a'] !=0]. does it help? – Hamid Feb 14 '19 at 20:24
2

@coldspeed no worry man , even with this `ne` still a simple dup question – BENY Feb 14 '19 at 20:30
Thanks @Wen-Ben, it's perfect – Gregor D Feb 14 '19 at 20:46

0 Answers0