sub

Lesson 5 of 28 in Coddy's RegEx in Python course.

The sub function is used to replace occurrences of a pattern in a string with a specified replacement string. It's a powerful tool for performing search-and-replace operations with regular expressions.

re.sub(pattern, repl, string, count=0)

pattern: The regular expression pattern to search for.
repl: The replacement string.
string: The string in which to search and replace.
count: Optional. The maximum number of replacements to perform. The default value is 0, which means replace all occurrences.

import re

text = "I have 2 apples and 3 bananas."
pattern = r"\d"  # This pattern matches any digit
replacement = "#"

result = re.sub(pattern, replacement, text)

print(result)  # Output: I have # apples and # bananas.

In the above example, we used the sub function to replace all digits in the string text with the replacement string "#". The result is a new string with the replacements made.

Challenge

Easy

Write a program that uses the sub function to replace all occurrences of the word "Python" with "JavaScript" in the string "Python is great. I love Python!". Print the result at the end.

Try it yourself

import re

text = "Python is great. I love Python!"

# Write code here

All lessons in RegEx in Python

1Introduction

Introduction

4Anchors and Quantifiers

Anchors Boundaries Quantifiers Repetitions

7Final Challenges

Extracting Hashtags Finding Email Addresses Valid Phone Numbers Finding Dates Capitalized Words

2re Library

findall search splitsub

5Grouping and Advanced Patterns

Grouping Capturing Pipe Operator Alternation Lookaheads Lookbehinds

3Basic Pattern Syntax

Basic Metacharacters Literals Character Classes Ranges Common Predefined Classes Advanced Predefined Classes

6Advanced Techniques

Escape Metacharacters Escape Sequences