preg_match_gf()

Run a regular expression against a string and return a single capture group — a one-liner for "match and extract" without handling a matches array yourself.

Syntax

preg_match_gf(pattern, subject, index)

Parameters

Name	Type	Required	Description
`pattern`	string	yes	The regex pattern (e.g. `'/order-(\d+)/'`).
`subject`	string	yes	The string to search.
`index`	int	yes	Which group to return: `0` = whole match, `1` = first capture group, etc.

Returns

The matched group as a string, or an empty string "" if there's no match.

Example

$id = preg_match_gf('/invoice #(\d+)/i', $record["subject"], 1);
if ( $id != "" ) sys_log("Invoice number: " . $id);

Example output

"4471"

Notes

Returns "" (not false/null) when nothing matches — test with != "".
For all matches of a group, use preg_match_all_gf(). Standard preg_match() / preg_replace() are also available.