Select column names where row values are not null pandas dataframe

Question

Here is a sample dataframe:-

 A      B    C
23     45  30
54     39  NaN
NaN    45  76
87     32  NaN

I want a list (or list of lists) that contains column names where row values are not NaN.

Expected Output:-

A B C
A B
B C
A B

What is the right way of doing this? Thanking you in anticipation.

anky · Accepted Answer · 2019-12-26 11:29:20Z

14

IIUC, you can use a .dot product of df.columns with df.notna():

df.notna().dot(df.columns+',').str.rstrip(',') #you can assign to a new column

0    A,B,C
1      A,B
2      B,C
3      A,B
dtype: object

answered Dec 26, 2019 at 11:23

anky

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1 Comment

Man wish I could upvote this answer more than once. Smart way of using the matrix multiplication.