How to fill a column conditionally to values in an other column being in a list?

Question

In pandas dataframe, how to fill the value of a column conditionally to values in an other column being part of a list ?

This is very similar to this SO question, but when I apply:

df['type'] = np.where(df['food'] in ['apple', 'banana', 'kiwi'], 'fruit', 'oth. food')

I got an error:

ValueError: The truth value of a Series is ambiguous. Use a.empty, a.bool(), a.item(), a.any() or a.all().

I suppose the in operator has been not overridden to work with vectors..

Are you after `df['type'] = np.where(df['food'].isin(['apple', 'banana', 'kiwi']), 'fruit', 'oth. food')` — EdChum, Apr 11 '16 at 14:12

score 7 · Accepted Answer · answered Apr 11 '16 at 14:12

7

this should work

df['type'] = np.where(df['food'].isin(['apple', 'banana', 'kiwi']), 'fruit', 'oth. food')

answered Apr 11 '16 at 14:12

1

:) only 20 seconds is between our posts. Nice. – jezrael Apr 11 '16 at 14:14
@jezrael: thanks both.. I would love I could add both as accepted answers ;-) – Antonello Apr 11 '16 at 14:19
yeah, if only you could add both :-) – Mohamed Ali JAMAOUI Apr 11 '16 at 14:19
I think what can I do in your skin - maybe only upvote both solutions. But you lost `+2`, hmmm. But it is up to you, what do you do. – jezrael Apr 11 '16 at 14:23
No problem. Nice day. – jezrael Apr 12 '16 at 07:04
I think that it is not problem with accepting MedAli solution. Thank you for upvoting. Difference 20 seconds is nearly the same. :P – jezrael Apr 12 '16 at 09:01

score 3 · Answer 2 · answered Apr 11 '16 at 14:12

3

I think you can use isin:

df['type'] = np.where(df['food'].isin(['apple', 'banana', 'kiwi']), 'fruit', 'oth. food')

answered Apr 11 '16 at 14:12

jezrael

2 Answers2