Pandas DataFrame interpolate() Method
Example
Replace NULL values with the number between the previous and next row:
In this example we use a .csv file called data.csv
import pandas as pd
df = pd.read_csv('data.csv')
newdf = df.interpolate(method='linear')
Try it Yourself »
Definition and Usage
The interpolate() method replaces the NULL values
based on a specified method.
Syntax
dataframe.interpolate(method, axis, inplace, limit, limit_direction,
limit_area, downcast, kwargs)
Parameters
The parameters are keyword arguments.
| Parameter | Value | Description |
|---|---|---|
| method | 'linear' |
Optional, default 'linear' . Specifies the method to use when replacing NULL values |
| axis | 0 |
Optional, default 0. The axis to fill the NULL values along |
| inplace | True |
Optional, default False. If True: the replacing is done on the current DataFrame. If False: returns a copy where the replacing is done. |
| limit | NumberNone |
Optional, default None. Specifies the maximum number of NULL values to fill (if method is specified) |
| limit_direction | 'forward' |
Optional, default 'forward', (if the method is backfill or bfill, the default limit_direction is 'backward'. Specifies the direction of the filling. |
| limit_area | None |
Optional, default None. Specifies restricitons of the filling: None - No restrictions 'inside' - Fill only NULL values inside valid values 'outside' - Fill only NULL values outside valid values |
| downcast | DictionaryNone |
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.
