match

Returns the first match of a regular expression, or one of its capture groups.

Details #

match(text, pattern, group?) takes two or three arguments.

Returns the first match of pattern as text. With no group, that is the whole match.
group is a number: 0 is the whole match, 1 the first parenthesised group, and so on.
Returns null (nothing) when the pattern doesn't match, so test the result before using it: match(s, "[0-9]+") ? ... : ....

The pattern is a regular expression (ICU syntax) and is case-sensitive.

Takes 2 to 3 arguments. {{ match(text, b, c?) }}

match("order 1234 shipped", "[0-9]+")

→ 1234

match("key=value", "(.*)=(.*)", 2)

→ value

match("no digits", "[0-9]+") == null

→ true

A group number the pattern doesn't have is an error: match() group 3 doesn't exist in that pattern. A group that exists but matched nothing gives null.
An invalid pattern is an error: '(' isn't a valid regular expression.
Matching is not anchored. Add ^ and $ to test the whole text.
Backslashes in quotes need doubling ("\\d+"), or use [0-9].