Python-pandas, np.nan

Question

Could you guys please help me explain the code below:

Why a nan is not np.nan?

import pandas as pd
import numpy as np

df.iloc[31464]['SalesPersonID']
[out]:
nan

df.iloc[31464]['SalesPersonID'] is np.nan
[out]:
False

Thank you, all.

[How to check if any value is NaN in a Pandas DataFrame](https://stackoverflow.com/questions/29530232/) — Trenton McKinney, Aug 22 '20 at 03:48
Related: [Why in numpy `nan == nan` is False while `nan in [nan]` is True?](https://stackoverflow.com/questions/20320022/why-in-numpy-nan-nan-is-false-while-nan-in-nan-is-true) — Stefan, Aug 22 '20 at 05:53

score 7 · Answer 1 · answered Aug 22 '20 at 03:16

np.nan is a special value in numpy. Read here for more information on it.

The link above mentions the following code snippet:

>>> np.nan == np.nan  # is always False! Use special numpy functions instead.

Also, type(df.iloc[31464]['SalesPersonID']) is np.float64.

score 3 · Answer 2 · edited Aug 22 '20 at 07:28

3

use np.isnan(np.nan) which gives True or

np.isnan(df.iloc[31464]['SalesPersonID']) which gives True

edited Aug 22 '20 at 07:28

Stefan

answered Aug 22 '20 at 03:42

Anurag Dhadse

Great help! Thanks, all. – Vinh Nguyen Aug 22 '20 at 13:50
1

mark an answer as approved. whichever has helped you. – Anurag Dhadse Aug 22 '20 at 16:53

2 Answers2