How can I count the number of NaNs in a column until the first non-NaN value in pandas?

Asked Jan 05 '22 at 07:55

Active Jan 05 '22 at 08:04

Viewed 77 times

I have the following dataframe:

Column A	Column B
Lorem	NaN
Ipsum	NaN
Dolor	NaN
Sit	25
Amet	34
Etc	NaN
Something else	NaN

I would like to count the number of NaNs in Column B until the first non-NaN number (which is 25 here). So, the expected returned value is 3.

I think there is something involving notna() and first_valid_index, but I cannot seem to put the information together. This problem is similar to this one but I want before, not since the first NaN.

Can you help me?

asked Jan 05 '22 at 07:55

Bogdan Doicin

2,342
5
25
34

6

As you mentioned, `df["Column B"].first_valid_index()` :ğ – Mustafa Aydın Jan 05 '22 at 07:57
2

I've upvoted the @MustafaAydın's comment. it is the valid answer. Just one remark: if all the values are valid , the function will return `None` – Marcel Preda Jan 05 '22 at 08:10
I really can't see how this question is a duplicate of the mentioned question! – Arigion Jun 22 '22 at 11:23

How can I count the number of NaNs in a column until the first non-NaN value in pandas?

0 Answers0