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Pandas DataFrame ffill() Method

❮ DataFrame Reference


Example

Replace NULL values with the value from the previous row:

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

import pandas as pd

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

newdf = df.ffill()
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Definition and Usage

The ffill() method replaces the NULL values with the value from the previous row (or previous column, if the axis parameter is set to 'columns').


Syntax

dataframe.ffill(axis, inplace, limit, downcast)

Parameters

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

Parameter Value Description
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
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