Common Predefined Classes

Lesson 10 of 28 in Coddy's RegEx in Python course.

Predefined character classes simplify the process of writing regular expressions by providing shortcuts for commonly used character classes. Here are some of the most commonly used predefined character classes:

\d: Matches any digit (equivalent to [0-9]).
\w: Matches any word character, which includes letters, digits, and underscores (equivalent to [a-zA-Z0-9_]).
\s: Matches any whitespace character, including spaces, tabs, and line breaks (equivalent to [ \t\n\r\f\v]).

import re

text = "I have 2 apples and 3 bananas."
pattern = r"\d"

matches = re.findall(pattern, text)

print(matches)  # Output: ['2', '3']

In the above example, the pattern \d matches any digit in the string text.

Challenge

Easy

Write a function named find_all_digits that takes a text string as input and returns a list of all digits found in the text.

Try it yourself

import re

def find_all_digits(text):
    # 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 split sub

5Grouping and Advanced Patterns

Grouping Capturing Pipe Operator Alternation Lookaheads Lookbehinds

3Basic Pattern Syntax

Basic Metacharacters Literals Character Classes RangesCommon Predefined ClassesAdvanced Predefined Classes

6Advanced Techniques

Escape Metacharacters Escape Sequences