Importing Regex and manipulating strings

Welcome to the tutorial on "Employing Regex and Shaping Strings"! We're about to dive into the world of regular expressions (Regex) in Python, taking a journey through the re module and its many utilities. The re module is a toolbox for everything from pattern matching to string division, and all it takes to unlock these tools is a simple import statement. Let's get started!

Kick off by drawing the re module into your Python script:

import re

Having brought in the re module, a myriad of Regex functions is now at your fingertips. Let's inspect some of the key functions:

re.match(pattern, string): Examines whether the pattern is present at the outset of the string. It offers a match object for a successful match, or None otherwise. For instance:

Python

import re

pattern = r"Hello"
string = "Hello, World!"

match = re.match(pattern, string)
if match:
    print("Pattern matched!")
else:
    print("No match found.")

In the above snippet, r"Hello" is pitted against "Hello, World!". A successful match at the string's start triggers the "Pattern matched!" message.

re.search(pattern, string): Hunts for the pattern's initial appearance within the string, returning a match object for a hit or None otherwise. As an example:

match = re.search(pattern, string)

Here, r"World" is sought in "Hello, World!". The pattern's presence prompts the "Pattern found!" message.

re.findall(pattern, string): Retrieves all instances of the pattern within the string, returning them in a list. For example:

Python

import re

pattern = r"\\d+"
string = "I have 3 apples and 5 oranges."

matches = re.findall(pattern, string)
print(matches)

The snippet uses r"\d+" to detect one or more digit characters in "I have 3 apples and 5 oranges.". With re.findall(), the result is ['3', '5'] - the discovered matches.

re.sub(pattern, repl, string): Sw…