How to use pandas apply function on all columns of some rows of data frame

Question

I have a dataframe. I want to replace values of all columns of some rows to a default value. Is there a way to do this via pandas apply function

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Answer 1

NumPy based method would be to use np.in1d to get such a mask and use it like so -

mask = np.in1d(temp.c,mylist)
temp.ix[mask,temp.columns!='c'] = 0

This will replace in all columns except 'c'. If you are looking to replace in specific columns, say 'a' and 'b', edit the last line to -

temp.ix[mask,['a','b']] = 0