First column name with non null value by row pandas

Question

I want know the first year with incoming revenue for various projects.

Given the following, dataframe:

ID  Y1      Y2      Y3
0   NaN     8       4
1         


        

Answer 1

Apply this code to a dataframe with only one row to return the first column in the row that contains a null value.

row.columns[~(row.loc[:].isna()).all()][-1]