Replace a sub-string in a string in Python

Understanding String Manipulation

Replacing a sub-string in a string means finding a specific sequence of characters and replacing it with another sequence.

We will explore three different methods to achieve this in Python.

Method 1: Using replace() Method

This method utilizes Python's built-in replace() function.

def replace_substring(text, old, new):
    return text.replace(old, new)

text = "Hello World!"
modified_text = replace_substring(text, "World", "Python")
print("Modified String:", modified_text)
            

Method 2: Using Recursion

This method replaces the sub-string recursively.

def replace_recursive(text, old, new):
    if old not in text:
        return text
    return replace_recursive(text.replace(old, new, 1), old, new)

text = "I love programming"
modified_text = replace_recursive(text, "love", "enjoy")
print("Modified String:", modified_text)
            

Method 3: Using Regular Expressions

This method uses Python's re module for pattern-based replacement.

import re

def replace_using_regex(text, old, new):
    return re.sub(re.escape(old), new, text)

text = "Replace old text"
modified_text = replace_using_regex(text, "old", "new")
print("Modified String:", modified_text)