<?php
preg_match("/(?P<foo>abc)(.*)(?P<bar>xyz)/",
           'abcdefghijklmnopqrstuvwxyz',
           $matches);
print_r($matches);
?>
------------------------------
Array
(
    [0] => abcdefghijklmnopqrstuvwxyz
    [foo] => abc
    [1] => abc
    [2] => defghijklmnopqrstuvw
    [bar] => xyz
    [3] => xyz
)