DataFrame.replace()

This method is used to replace null or null values with a specific value.

Syntax: DataFrame.replace(self, to_replace=None, value=None, inplace=False, limit=None, regex=False,                         method=’pad’)

Parameters: This method will take following parameters:

  • to_replace(str, regex, list, dict, Series, int, float, None): Specify the values that will be replaced.
  • value(scalar, dict, list, str, regex, default value is None): Specify the value to replace any values matching to_replace with.
  • inplace(bool, default False): If a value is True, in place. Note: this will modify any other views on this object.
  • limit(int, default None): Specify the maximum size gap to forward or backward fill.
  • regex(bool or same types as to_replace, default False): If a value is True then to_replace must be a string. Alternatively, this could be a regular expression or a list,  dict, or array of regular expressions in which case to_replace must be None.
  • method {‘pad’, ‘ffill’, ‘bfill’, None}: Specify the method to use when for replacement, when to_replace is a scalar, list or tuple and value is None.

Returns: DataFrame. Object after replacement.

Code: Create a Dataframe.

Python3




# Import Pandas Library
import pandas as pd
 
# Import Numpy Library
import numpy as np
 
# Create a DataFrame
df = pd.DataFrame([[np.nan, 2, 3, np.nan],
                   [3, 4, np.nan, 1],
                   [1, np.nan, np.nan, 5],
                   [np.nan, 3, np.nan, 4]])
 
# Show the DataFrame
print(df)


Output:

Code: Replace all the NaN values with Zero’s

Python3




# Filling null values with 0
df = df.replace(np.nan, 0)
 
# Show the DataFrame
print(df)


Output:



Replace all the NaN values with Zero’s in a column of a Pandas dataframe

Replacing the NaN or the null values in  a dataframe can be easily performed using a single line DataFrame.fillna() and DataFrame.replace() method. We will discuss these methods along with an example demonstrating how to use it.

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DataFrame.fillna():

This method is used to fill null or null values with a specific value....

DataFrame.replace():

...