Regex Fundamentals
Learn metacharacters, character classes, quantifiers, and anchors.
Regex Fundamentals is a free Python Academy lesson on CoddyKit — lesson 1 of 4. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the Python Academy learning path, one of 4 lessons in the course, and your progress syncs across the web and the CoddyKit app.
Introduction
What is a Regex?
import re
print(re.findall(r'\d+', 'abc 123 def 456'))Literal Characters
import re
print(re.search(r'cat', 'the cat sat'))Dot (.) Wildcard
import re
print(re.findall(r'c.t', 'cat cut c9t caaat'))Character Classes
import re
print(re.findall(r'[aeiou]', 'hello world'))Quantifiers
import re
print(re.findall(r'\d{2,4}', '1 12 123 1234 12345'))Anchors
import re
print(re.findall(r'^\w+', 'hello world'))
print(re.findall(r'\b\w{4}\b', 'cat cats come home'))Shorthand Classes
import re
print(re.findall(r'\w+', 'hello, world!'))Alternation |
import re
print(re.findall(r'cat|dog', 'I have a cat and a dog'))Greedy vs Lazy
import re
html = '<b>bold</b> and <i>italic</i>'
print(re.findall(r'<.*>', html)) # greedy
print(re.findall(r'<.*?>', html)) # lazyRaw Strings for Regex
import re
# Without r: '\\d+' is needed
# With r: '\d+' is sufficient
print(re.findall(r'\d+', 'abc123'))Quick Check
Recap
Keep Going
Frequently asked questions
Is the “Regex Fundamentals” lesson free?
Yes — the full text of “Regex Fundamentals” is free to read here on the web, and the Python Academy course includes 4 lessons in total. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the Python Academy course, upgrade to CoddyKit PRO.
What will I learn in “Regex Fundamentals”?
Learn metacharacters, character classes, quantifiers, and anchors. You practise Python Academy with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.
Do I need any experience to start Python Academy?
No prior experience is required. Python Academy on CoddyKit is structured for beginners through advanced learners; this is — lesson 1 of 4, so you can start here or from the beginning and move at your own pace.
How long does the “Regex Fundamentals” lesson take?
Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.
Can I write and run code in this Python Academy lesson?
Yes. Every Python Academy lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.