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Pandas DataFrame fillna() Method

❮ DataFrame Reference


Example

Replace NULL values with the number 222222:

In this example we use a .csv file called data.csv

import pandas as pd

df = pd.read_csv('data.csv')

newdf = df.fillna(222222)
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Definition and Usage

The fillna() method replaces the NULL values with a specified value.

The fillna() method returns a new DataFrame object unless the inplace parameter is set to True, in that case the fillna() method does the replacing in the original DataFrame instead.


Syntax

dataframe.fillna(value, method, axis, inplace, limit, downcast)

Parameters

The axis, method, inplace, limit, downcast parameters are keyword arguments.

Parameter Value Description
value Number
String
Dictionary
Series
DataFrame
Required, Specifies the value to replace the NULL values with.
This can also be values for the entire row or column.
method 'backfill'
'bfill'
'pad'
'ffill'
None
Optional, default None'. Specifies the method to use when replacing
axis 0
1
'index'
'columns'
Optional, default 0. The axis to fill the NULL values along
inplace True
False
Optional, default False. If True: the replacing is done on the current DataFrame. If False: returns a copy where the replacing is done.
limit Number
None
Optional, default None. Specifies the maximum number of NULL values to fill (if method is specified)
downcast Dictionary
None
Optional, a dictionary of values to fill for specific data types

Return Value

A DataFrame with the result, or None if the inplace parameter is set to True.


❮ DataFrame Reference