- preg_match: documentation ( source)
- print_r: documentation ( source)
- preg_match_all: documentation ( source)
<?php
// 1. Identify the block of <a> elements
$string = '<div><a href=%http://link1%><img></a><a href=%http://link2%><img></a><a href=%http://link3%><img></a></div>';
$re = '|<div>((<a((?!href)(?!<).)+?href=%([^%]+?)%((?!</a>).)+?</a>){3})</div>|';
$matches = array();
echo('result='.intval(preg_match($re, $string, $matches))."\n");
echo('$matches='); print_r($matches);
// 2. Extract the URLs
$re = '|<a((?!href)(?!<).)+?href=%([^%]+?)%((?!</a>).)+?</a>|';
$URLs = array();
preg_match_all($re, $matches[1], $URLs);
echo('URLs='); print_r($URLs[2]);