Regular expressions look like keyboard soup, but they're built from a small set of pieces. Learn those pieces and you can search, validate, and extract text in almost any language or editor. Here's the beginner's cheat sheet.
Key takeaways
- A regex is a pattern that describes text you want to match.
- Character classes match types of characters; quantifiers set how many.
- Anchors pin a match to the start or end.
- Always test a pattern on real samples.
The essential tokens
| Token | Matches |
|---|---|
. | Any single character (except newline) |
\d / \D | A digit / a non-digit |
\w / \W | A word char (a–z, 0–9, _) / non-word |
\s / \S | Whitespace / non-whitespace |
[abc] | Any one of a, b, or c |
[^abc] | Any character except a, b, c |
[a-z] | Any character in the range |
Quantifiers (how many)
| Token | Means |
|---|---|
* | 0 or more |
+ | 1 or more |
? | 0 or 1 (optional) |
{3} | Exactly 3 |
{2,4} | Between 2 and 4 |
Anchors & groups
^— start of the string$— end of the string\b— a word boundary( )— a capture group( | )— "or"
Test your pattern live
Type a regex and sample text and see matches highlight instantly.
Open the Regex Tester →Practical examples
\d{4} → a 4-digit year, e.g. 2026
^\d{3}-\d{4}$ → a phone like 555-1234
\b\w+@\w+\.\w+\b → a simple email shape
#[0-9A-Fa-f]{6} → a HEX colour like #2D6CDF
\s+ → one or more spaces (great for cleanup)Beginner tips
- Escape special characters with a backslash to match them literally:
\.matches a real dot. - Quantifiers are greedy by default; add
?(e.g..+?) to make them lazy. - Build incrementally and test after each piece.
- Don't parse HTML with regex — use a real parser for nested structures.
Frequently asked questions
What is a regular expression?
A pattern that describes the text you want to find, validate, or extract.
What does \d mean?
Any single digit 0–9. \D matches any non-digit.
Greedy vs lazy?
Quantifiers grab as much as possible by default; add ? to match as little as possible.
Related tools
See our Disclaimer for how to use WorkIQ content and tools.