$data =

this is a test string

$regexp =

/test/i

preg_match_all($regexp, $data, $matches)preg_match_all($regexp, $data, $matches, PREG_PATTERN_ORDER)preg_match_all($regexp, $data, $matches, PREG_OFFSET_CATPURE)preg_replace($regexp, '\1, \2, \3, \4, \5', $data)preg_match($regexp, $data, $matches)preg_split($regexp, $data)

1

$matches =

Array
(
    [0] => Array
        (
            [0] => test
        )

)