How to change dataframe column with no warning "A value is trying to be set on a copy of a slice from a DataFrame"

Asked Jul 15 '16 at 07:46

Active Jul 15 '16 at 08:04

Viewed 1,346 times

I have a dataframe wich name is "data" with 97230 rows and 4 columns. Name one of columns for example is "A". Also i have some variables: "indVec" - bool series with same index as "data"; valVec - vector with some values. sum(indVec)=len(indVal) I am trying to set value for column 'A' in index "indVec" by different ways. But every time i get this message:

"A value is trying to be set on a copy of a slice from a DataFrame

See the caveats in the documentation: http://pandas.pydata.org/pandas-docs/stable/indexing.html#indexing-view-versus-copy self._setitem_with_indexer(indexer, value)"

Ways, that i am using to set values for 'A' column of dataframe "data":

data.loc[indVec,'A']=valVec
data.ix[indVec,'A']=valVec
data.set_value[indVec,'A']=valVec
data.A[indVec]=valVec

How can I set value for column 'A' without this message?

edited Jul 15 '16 at 08:04

EdChum

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asked Jul 15 '16 at 07:46

K.Alex

Is `data` a slice of another dataframe? The things you have tried should work. – ayhan Jul 15 '16 at 07:51
You'll need to post raw data and code that reproduces this, if you filtered the df prior to these calls then this warning will be raised – EdChum Jul 15 '16 at 08:05
This might be helpful http://stackoverflow.com/a/38147527/2336654 – piRSquared Jul 15 '16 at 08:22
Thanks a lot! You were right. "Dataframe.copy()" solved this problem! – K.Alex Jul 15 '16 at 11:52
mute all warning. https://stackoverflow.com/questions/15777951/how-to-suppress-pandas-future-warning – Vae Jiang Apr 11 '22 at 20:31

How to change dataframe column with no warning "A value is trying to be set on a copy of a slice from a DataFrame"

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