Highlight Pandas DataFrame's specific columns using applymap()

Let us see how to highlight elements and specific columns of a Pandas DataFrame. We can do this using the applymap() function of the Styler class.

Styler.applymap() 

Syntax : Styler.applymap(self, func, subset = None, **kwargs) Parameters :

• func : takes a scalar and returns a scalar.
• subset : valid indexer to limit data to before applying the function.
• **kwargs : dict pass along to func.

Returns : Styler

Let's understand with examples:

First of all create a simple data frame:

python3

# importing pandas as pd 
import pandas as pd 

# creating the dataframe  
df = pd.DataFrame({"A" : [14, 4, 5, 4, 1], 
                   "B" : [5, 2, 54, 3, 2],
                   "C" : [20, 20, 7, 3, 8],
                   "D" : [14, 3, 6, 2, 6]}) 

print("Original DataFrame :")
display(df)

Output : Example 1 : For every cell in the DataFrame, if the value is less than 6 then we will highlight the cell with red color, otherwise with blue color. Python3

# function definition
def highlight_cols(s):
    color = 'red' if s < 6 else 'blue'
    return 'background-color: % s' % color

# highlighting the cells
display(df.style.applymap(highlight_cols))

Output : Example 2 : This time we will highlight only the cells in some specified columns. Python3

# function definition
def highlight_cols(s):
    return 'background-color: % s' % 'yellow'

# highlighting the cells
display(df.style.applymap(highlight_cols, 
                          subset = pd.IndexSlice[:, ['B', 'C']]))

Output :

Highlight specific columns with the help of Indexing:

Python3

df.style.applymap(highlight_cols, subset = pd.IndexSlice[:, ['B', 'C']])