Pandas 将第一个 NaN 之后的所有值设置为 NaN

Question

For each row I would like to set all values to NaN after the appearance of the first NaN. Eg:

    a    b    c    
1   2    3    4    
2   nan  2    nan  
3   3    nan  23   

Should become this:

    a    b    c    
1   2    3    4    
2   nan  nan  nan  
3   3    nan  nan

So far I only know how to do this with an apply with a for loop over each column per row - it's very slow!

Answer 1

Check with cumprod

df=df.where(df.notna().cumprod(axis=1).eq(1))
     a    b    c
1  2.0  3.0  4.0
2  NaN  NaN  NaN
3  3.0  NaN  NaN