isna search on mulitple columns/rows gives error: duplicate columns & possible reduce dimensionality

Question

I'm trying to search for NaN values in different columns and rows and want to show all rows.

My dataset:

import pandas as pd
df = pd.read_excel('./file.xlsx')
df = df.replace(' ', np.nan)
df.head()
 
                             col1    col2      col3

row1                         NaN     NaN       test
row2                         hello   twon      street
row3                         words   place     NaN
row4                         NaN     towns     places
row5                         town    NaN       NaN  

I tried this:

nan_rows = df[df['col1', 'col2', 'col3'].isna().any(axis=1)]

This gives a key-error:

  2693         # get column
   2694         if self.columns.is_unique:
-> 2695             return self._get_item_cache(key)
   2696 
   2697         # duplicate columns & possible reduce dimensionality

Expected result:

                             col1    col2      col3

row1                         NaN     NaN       test
row3                         words   place     NaN
row4                         NaN     towns     places
row5                         town    NaN       NaN

Appreciate the help and effort. Thank you!

Answer 1

You need double square brackets to slice with a list of columns:

df[df[['col1', 'col2', 'col3']].isna().any(axis=1)]

Alternative using a named list:

cols = ['col1', 'col2', 'col3']

df[df[cols].isna().any(axis=1)]

output:

       col1   col2    col3
row1    NaN    NaN    test
row3  words  place     NaN
row4    NaN  towns  places
row5   town    NaN     NaN