array_key_vs_isset.php

<?php

$data = array();
$time = array();
for ($i = 97; $i < 173; $i++)
    $data[chr($i)] = $i;

$s = microtime(true);
for ($i = 0; $i < 1000000; $i++) {
    isset($data['g']);
}
$time['isset'] = microtime(true)-$s;
printf("isset time:\t\t\t%f\n", $time['isset']);


$s = microtime(true);
for ($i = 0; $i < 1000000; $i++) {
    array_key_exists('g', $data);
}
$time['array_key_exists'] = microtime(true)-$s;
printf("array_key_exists time:\t\t%f\n", $time['array_key_exists']);

if ($time['isset'] < $time['array_key_exists'])
    printf("isset is faster by:\t\t %.2f%%", (($time['array_key_exists']-$time['isset'])*100/$time['isset']));
else
    printf("array_key_exists is faster by:\t %.2f%%", (($time['isset']-$time['array_key_exists'])*100/$time['array_key_exists']));