Character Classes

In regular expressions, character classes are used to match specific sets of characters. They allow you to define a group of characters that you want to match within a given text.

For example, let's say you want to match any vowel in a string. You can use the character class [aeiou] to specify that you want to match any character that is either 'a', 'e', 'i', 'o', or 'u'.

Here's an example of using character classes in a regular expression:

1import re
2
3# Create a regex pattern that matches any vowel
4pattern = r'[aeiou]'
5
6# Create a test string
7string = 'AlgoDaily is amazing'
8
9# Use the findall() function to find all matches
10matches = re.findall(pattern, string)
11
12# Print the matches
13print(matches)

In this example, the character class [aeiou] matches all the vowel characters in the string 'AlgoDaily is amazing'. The re.findall() function is used to find all the matches of the pattern in the string, and it returns a list of all the matches.

Character classes can also include ranges of characters. For example, [a-z] matches any lowercase letter, and [0-9] matches any digit.

Keep in mind that character classes are case-sensitive by default. To make them case-insensitive, you can use the re.IGNORECASE flag as an optional argument.