Pattern Matching

Letters '[a-zA-Z]'

Control Characters

Digits '[0-9]'

Lowercase Letters

Punctuation Characters

Whitespace Characters (ie. space, tabs, newline, etc.)

Uppercase Letters

Alphanumeric Characters (equivalent to %a and %d combined)

Hexadecimal Digits '[0-9a-fA-F]'

Null Character.

A character class set allows you to match any one character from the enclosed set.

string.match("abcd", "[beta]")

-- returns a

A capture allows you to enclose sub patterns in your pattern. You can capture multiple patterns.

local field, value = string.match("id: 123456", '(%a+):%s*(%d+)')
-- returns id, 123456

Represents any single character.

string.match("abcd", "a..d")
-- returns abcd

An escape can be used to escapes the following character, treating it as a literal character instead of a magic character.

string.match("50% off today!", "(%d+)%%")
-- returns 50

When used at the beginning of a pattern, it forces the pattern to match the start of a string.

When used inside [ ], the meaning of ^ becomes NOT.

string.match("abcd", "^%a")
-- returns a

string.match("abcd", "[^ad]")
-- returns b

When used at the end of a pattern, it forces the pattern to match the end of the string.

string.match("abcd", "%a$")
-- returns d

Matches 1 or more repetitions. It will always match the longest possible chain.

string.match("foo 123 bar", "%d+")
-- returns 123

Matches 0 or more repetitions. This will always match the shortest possible chain.

When used inside [ ], the meaning of - becomes a range.

string.match("abcd", "abc-")
-- returns ab

string.match("123", "[0-9]")
-- returns 1

Matches 0 or more repetitions. This will always match the longest possible chain.

string.match("abcd", "abc*")
-- returns abc

Optional can match 0 or 1 occurrence.

string.match("abc", "abcd?")
-- returns abc