Pandas DataFrame select the specific columns with NaN values

Question

I have a two-column DataFrame, I want to select the rows with NaN in either column.

I used this method df[ (df['a'] == np.NaN) | (df['b'] == np.NaN) ]
However it returns an empty answer. I don't know what's the problem

Answer 1

You need isnull for finding NaN values:

df[ (df['a'].isnull()) | (df['b'].isnull()) ]

Docs.