Regex Cheatsheet

A quick reference for common Regular Expression patterns and syntax.

Anchors

Pattern Description
^ Matches the beginning of the string.
$ Matches the end of the string.
\b Matches a word boundary.
\B Matches a non-word boundary.

Character Classes

Pattern Description
. Matches any single character except newline.
\d Matches any digit (0-9).
\D Matches any non-digit.
\w Matches any word character (alphanumeric & underscore).
\W Matches any non-word character.
\s Matches any whitespace character (space, tab, newline).
\S Matches any non-whitespace character.
[abc] Matches any character in the set (a, b, or c).
[^abc] Matches any character not in the set.
[a-z] Matches any character in the range a to z.

Flags / Modifiers

Pattern Description
g Global search (don't return after the first match).
i Case-insensitive search.
m Multi-line search.

Grouping and Capturing

Pattern Description
(...) Captures the matched group.
(?:...) Non-capturing group.
| Acts like a boolean OR. Matches the expression before or after the |.

Quantifiers

Pattern Description
* Matches 0 or more repetitions of the preceding character.
+ Matches 1 or more repetitions of the preceding character.
? Matches 0 or 1 repetition of the preceding character.
{n} Matches exactly n repetitions.
{n,} Matches n or more repetitions.
{n,m} Matches between n and m repetitions.

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