How to filter in NaN (pandas)?

Simplest of all solutions:

filtered_df = df[df['var2'].isnull()]

This filters and gives you rows which has only NaN values in 'var2' column.

This doesn't work because NaN isn't equal to anything, including NaN. Use pd.isnull(df.var2) instead.

df[df['var'].isna()]

where

df  : The DataFrame
var : The Column Name