<?php
$string = 'Chello said Hello, i said <a>after arriving say hello</a>';
$regex = '/<a>.*?<\/a>|\b(hello)\b/ims';
foreach($matches as $key=>$value){
if ($value[1]) {
echo $key . "=" . $value[0];
}
}
PD9waHAKCiAgICAkc3RyaW5nID0gJ0NoZWxsbyBzYWlkIEhlbGxvLCBpIHNhaWQgPGE+YWZ0ZXIgYXJyaXZpbmcgc2F5IGhlbGxvPC9hPic7CiAgICAkcmVnZXggPSAnLzxhPi4qPzxcL2E+fFxiKGhlbGxvKVxiL2ltcyc7CgogICAgcHJlZ19tYXRjaF9hbGwoJHJlZ2V4LCAkc3RyaW5nLCAkbWF0Y2hlcyk7CiAgICAKICAgIGZvcmVhY2goJG1hdGNoZXMgYXMgJGtleT0+JHZhbHVlKXsKICAgICAgICBpZiAoJHZhbHVlWzFdKSB7CiAgICAJICAgIGVjaG8gJGtleSAuICI9IiAuICR2YWx1ZVswXTsKICAgICAgICB9CgkgICAgfQoK