multiplication of two columns in dataframe SettingWithCopyWarning

Question

I`ve a large dataframe, Im trying to do a simple multipication between two columns and put the results in new column when I do that I'm getting this error message :

SettingWithCopyWarning : a value is trying to be set on a copy of a slice from a dataframe.

my code looks like this :

DF[‘mult‘]=DF[‘price‘]*DF[‘rate‘]

I Tried loc but didnt work .. does anyone have a solution ?

Does [this](https://stackoverflow.com/questions/20625582/how-to-deal-with-settingwithcopywarning-in-pandas) answer your question? — Jaroslav Bezděk, Mar 22 '20 at 12:37
What you're doing is right, please add some extra code to reproduce the warning. — Edoardo Guerriero, Mar 22 '20 at 12:39
it's possible that he/she already have a column named 'mult' — Artem Trunov, Mar 22 '20 at 12:44

score 0 · Answer 1 · answered Mar 22 '20 at 12:39

0

You should use df.assign() in this case:

df2 = DF.assign(mult=DF[‘price‘]*DF[‘rate‘])

You get back a new dataframe with a 'mult' column added.

answered Mar 22 '20 at 12:39

Artem Trunov

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multiplication of two columns in dataframe SettingWithCopyWarning

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