Highlight the nan values in Pandas Dataframe

Last Updated : 26 Jul, 2020

In this article, we will discuss how to highlight the NaN (Not a number) values in Pandas Dataframe. NaN values used to represent NULL values and sometimes it is the result of the mathematical overflow.
Lets first make a dataframe:

Python3

# Import Required Libraries 
import pandas as pd 
import numpy as np 
  
# Create a dictionary for the dataframe 
dict = {'Name': ['Sumit Tyagi', 'Sukritin', 'Akriti Goel', 
                 'Sanskriti', 'Abhishek Jain'], 
        'Age': [22, 20, np.nan, np.nan, 22], 
        'Marks': [90, 84, 33, 87, 82]} 
  
# Converting Dictionary to Pandas Dataframe 
df = pd.DataFrame(dict) 
  
# Print Dataframe 
df

Output:

Now, come to the highlighting part. Our objective is to highlight those cells which have Nan values.

Method 1: Highlighting Cell with nan values

We can do this by using the highlight_null() method of DataFrame.style property.This is a property that returns a Styler object, which has useful methods for formatting and displaying DataFrames. highlight_null() method requires one string parameter (the name of the colour with which you want to highlight the cell).

Example:

Python3

# Highlighting cell with nan values 
df.style.highlight_null('red')

Output:

Method 2: Highlighting text with nan values instead of background

We can do this by using applymap() method of the style property. applymap() method requires a function that takes a scalar and returns a scalar.
Example:

Python3

# Highlighting text instead of the  
# cell's background 
df.style.applymap(lambda cell: 'color:red' if pd.isnull(cell) else '')

Output:

Method 3: Highlighting the text of the complete row with nan values

We can do this using the apply() method
Example:

Python3

# Highlighting text of the complete row 
df.style.apply(lambda row: np.repeat('color: red' if row.isnull().any() else '', 
                                     row.shape[0]), axis=1)

Output:

Method 4: Highlighting the complete row with nan values

Python3

# Highlighting the complete row 
df.style.apply(lambda row: np.repeat('background: red' if row.isnull().any() else '', row.shape[0]), axis=1) 

Output:

Solution 5: Highlighting the whole column with nan values

Python3

# Highlighting column with nan values 
df.style.apply(lambda row: np.repeat('background: red' if row.isnull().any() else '', 
                                                                row.shape[0]), axis=0) 