- array_intersect_key: documentation ( source)
- chr: documentation ( source)
- array_flip: documentation ( source)
- rand: documentation ( source)
<?php
$size = 100;
$b = array();
for ($i = 0; $i < $size; $i++) {
$b[] = chr(rand(64,128));
}
$a = array(0,3,4,2,6);
for ($i = 0; $i < 10000; $i++) {
$c = array_intersect_key($b, array_flip($a));
}