Python String replace() Method

The replace() method returns a new string where all occurrences of a specified substring are replaced with another substring. It does not modify the original string because Python strings are immutable.

Example : This example replaces every occurrence of a substring in the given string, creating a fully updated new string.

s = "Python is fun. Python is powerful."
res = s.replace("Python", "Coding")
print(res)

Coding is fun. Coding is powerful.

Syntax

string.replace(old, new, count)

Parameters:

• old: Substring to be replaced.
• new: Substring to insert in place of old.
• count (optional): Maximum number of replacements. If not provided, all occurrences are replaced.

Return Value: Returns a new string with the specified replacements. The original string remains unchanged.

Examples

Example 2: Here, only the first occurrence of a substring is replaced using the count parameter.

s = "apple apple apple"
res = s.replace("apple", "orange", 1)
print(res)

orange apple apple

Explanation: s.replace("apple", "orange", 1) replaces "apple" only once due to count=1.

Example 3: This example demonstrates that replace() treats uppercase and lowercase characters as different, replacing only exact matches.

s = "Hello World! hello world!"
res1 = s.replace("Hello", "Hi")
res2 = s.replace("hello", "hi")
print(res1)
print(res2)

Hi World! hello world!
Hello World! hi world!

Explanation:

• s.replace("Hello", "Hi") affects only the capitalized "Hello".
• s.replace("hello", "hi") affects only the lowercase "hello".