Regex Cheatsheet

Regular expressions — character classes, groups, lookarounds and common patterns

Regex Cheatsheet

53 entries · click to copy

🔤 Character Classes

Any character except newline

Word character [a-zA-Z0-9_]

Non-word character

Digit [0-9]

Non-digit

Whitespace (space, tab, newline)

Non-whitespace

Any vowel — custom set

Any character NOT in set

Lowercase a through z

Alphanumeric

⚓ Anchors

Start of string (or line with m flag)

End of string (or line with m flag)

Word boundary

Non-word boundary

Start of string (no multiline)

End of string (no multiline)

🔢 Quantifiers

0 or more (greedy)

1 or more (greedy)

0 or 1 (optional)

Exactly 3

3 or more

Between 3 and 6

0 or more (lazy — minimal match)

1 or more (lazy)

0 or 1 (lazy)

( ) Groups & Capturing

Capturing group

Non-capturing group

Named capturing group

Backreference to group 1

Backreference to named group

Alternation — a or b

Atomic group (no backtrack)

👀 Lookarounds

Lookahead — followed by abc

Negative lookahead — NOT followed by abc

Lookbehind — preceded by abc

Negative lookbehind — NOT preceded by abc

🚩 Flags

Case-insensitive

Global — find all matches

Multiline — ^ and $ match line start/end

Dotall — dot matches newline

Unicode mode

Global + case-insensitive

⭐ Common Patterns

Email address

URL (http/https)

International phone number (E.164)

Date YYYY-MM-DD

Password — min 8 chars, upper, lower, digit

Hex color code

IPv4 address (loose)

UUID v4

Blank / whitespace-only line

HTML comment

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