How to replace all occurrences of a character in a Python string

Overview

In Python, we can replace all occurrences of a character in a string using the following methods:

  • replace()
  • re.sub()

The replace() method

replace() is a built-in method in Python that replaces all the occurrences of the old character with the new character.

Syntax

"".replace(oldCharacter, newCharacter, count)
Syntax of replace()

Parameters

This method accepts the following parameters:

  • oldCharacter: This is the old character that will be replaced.
  • newCharacter: This is the new character that will replace the old character.
  • count: This is an optional parameter that specifies the number of times to replace the old character with the new character.

    Return value

    This method creates a copy of the original string, replaces all the occurrences of the old character with the new character, and returns it.

    Example

    string = "This is an example string"

    

    # replace all the occurrences of "i" with "I"

    result = string.replace("i", "I")

    

    # print result

    print(result)

    Explanation

    • Line 1: We declare a string.
    • Line 4: We use the replace() method to replace all the occurrences of i with I.
    • Line 7: We print the result to the console.

    Output

    In the output, we can see all the occurrences of i in the string are replaced with I.

    The re.sub() method

    We can also use regular expressions to replace all the occurrences of a character in a string. This can be done using re.sub() method.

    Syntax

    re.sub(oldCharacter, newCharacter, string)
    Syntax of re.sub()

    Parameters

    This method accepts the following parameters:

    • oldCharacter: This is the old character that will be replaced.
    • newCharacter: This is the new character that will replace the old character.
    • string: This is the string in which the characters are to be replaced.

      Return value

      This method creates a copy of the original string, replaces all the occurrences of the old character with the new character, and returns it.

      Example

      import re

      

      string = "This is an example string"

      

      # replace all the occurrences of "i" with "I"

      result = re.sub("i", "I", string)

      

      # print result

      print(result)

      Explanation

      • Line 1: We import the re module.
      • Line 3: We declare a string.
      • Line 6: We use the re.sub() method to replace all the occurrences of i with I.
      • Line 9: We print the result to the console.

      Output

      In the output, we can see all the occurrences of i in the string are replaced with I.

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