Slow Regexps
Its often beneficial to replace regular expressions with simpler functions that have the same effect.

With Regular Expression
<?php
if (preg_match ('/(.*)\@(.*)/'$data$matches)) {
    print 
$matches[2];
}
? >
Without Regular Expressions
<?php
$pos 
strrpos ('@'$data);
if (
$pos !== false) {
    print 
substr ($data$pos);
}
? >
Fast Regexps
In other cases it may help to use regular expressions instead of custom parse routines in your PHP code.