Python String – Replace first N occurrences

Python String – Replace first N occurrences

To replace the first n occurrences in a Python string, you can use string replace() method with the optional __count parameter.

In this tutorial, we shall see the step by step process to replace only the first n occurrences of an old substring with a new substring in a string, using string replace() method, with examples.

Steps to replace only the first N occurrences in a string

1. Given string in x.

x = "apple apple apple apple apple"

2. Given limit on the number of replacements in n.

n = 3

3. Given old substring, and new substring in old and new variables respectively.

old = 'apple'
new = 'fig'

4. Call replace() method on string x and pass the values: old, new, and n as arguments respectively. The replace() method returns a new string, where the old substring is replaced with new substring for only the first n number of occurrences of old substring in the string x.

x.replace(old, new, n)

Program

The complete program to replace only the first n occurrences in a Python string using replace() method is given below.

# Given string
x = "apple apple apple apple apple"

# Limit on number of replacements
n = 3

# Old and new strings
old = 'apple'
new = 'fig'

# Replace first n occurrences
result = x.replace(old, new, n)

# Print the result string
print(result)

Output

fig fig fig apple apple

We specified to replace only the first three occurrences of the old substring "apple" with a new replacement string "fig" in the original string.

Summary

In this Python Strings tutorial, we learned how to replace only the first n occurrences in a string based using replace() method, with examples.