Pandas DataFrame ffill() Method

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()

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