Often you may be interested in counting the number of missing values in a pandas DataFrame.

This tutorial shows several examples of how to count missing values using the following DataFrame:

import pandas as pd import numpy as np #create DataFrame with some missing values df = pd.DataFrame({'a': [4, np.nan, np.nan, 7, 8, 12], 'b': [np.nan, 6, 8, 14, 29, np.nan], 'c': [11, 8, 10, 6, 6, np.nan]}) #view DataFrame print(df) a b c 0 4.0 NaN 11.0 1 NaN 6.0 8.0 2 NaN 8.0 10.0 3 7.0 14.0 6.0 4 8.0 29.0 6.0 5 12.0 NaN NaN

**Count the Total Missing Values in Entire DataFrame**

The following code shows how to calculate the total number of missing values in the entire DataFrame:

df.isnull().sum().sum() 5

This tells us that there are **5 **total missing values.

**Count the Total Missing Values per Column**

The following code shows how to calculate the total number of missing values in each column of the DataFrame:

df.isnull().sum() a 2 b 2 c 1

This tells us:

- Column ‘a’ has
**2**missing values. - Column ‘b’ has
**2**missing values. - Column ‘c’ has
**1**missing value.

You can also display the number of missing values as a percentage of the entire column:

df.isnull().sum()/len(df)*100 a 33.333333 b 33.333333 c 16.666667

This tells us:

**33.33%**of values in Column ‘a’ are missing.**33.33%**of values in Column ‘b’ are missing.**16.67%**of values in Column ‘c’ are missing.

**Count the Total Missing Values per Row**

The following code shows how to calculate the total number of missing values in each row of the DataFrame:

df.isnull().sum(axis=1) 0 1 1 1 2 1 3 0 4 0 5 2

This tells us:

- Row 1 has
**1**missing value. - Row 2 has
**1**missing value. - Row 3 has
**1**missing value. - Row 4 has
**0**missing values. - Row 5 has
**0**missing values. - Row 6 has
**2**missing values.

**Additional Resources**

How to Find Unique Values in Multiple Columns in Pandas

How to Create a New Column Based on a Condition in Pandas