isset() vs in_array() - super simple test - no breaks

isset_vs_in_array.php

<?php

define('MAX', 100000);
define('NUM', 100);

$in = array('key');
for ($i = 0; $i < NUM; ++$i) {
    $in100[] = 'key' . $i;
}
$is = array('key' => true,);
for ($i = 0; $i < NUM; ++$i) {
    $is100['key' . $i] = true;
}


$mt = microtime(1);
for ($i = 0; $i < MAX; ++$i) {
    isset($is['key']);
}
printf('Small isset() exists: %e', microtime(1) - $mt);
echo PHP_EOL;

$mt = microtime(1);
for ($i = 0; $i < MAX; ++$i) {
    isset($is['key0']);
}
printf('Small isset() not exists: %e', microtime(1) - $mt);
echo PHP_EOL;


$mt = microtime(1);
for ($i = 0; $i < MAX; ++$i) {
    in_array('key', $in);
}
printf('Small in_array() exists: %e', microtime(1) - $mt);
echo PHP_EOL;

$mt = microtime(1);
for ($i = 0; $i < MAX; ++$i) {
    in_array('key0', $in);
}
printf('Small in_array() not exists: %e', microtime(1) - $mt);
echo PHP_EOL;


$mt = microtime(1);
for ($i = 0; $i < MAX; ++$i) {
    isset($is100['key1']);
}
printf('Big isset() exists near start: %e', microtime(1) - $mt);
echo PHP_EOL;

$mt = microtime(1);
for ($i = 0; $i < MAX; ++$i) {
    isset($is100['key98']);
}
printf('Big isset() exists near end: %e', microtime(1) - $mt);
echo PHP_EOL;

$mt = microtime(1);
for ($i = 0; $i < MAX; ++$i) {
    isset($is100['key']);
}
printf('Big isset() not exists near end: %e', microtime(1) - $mt);
echo PHP_EOL;


$mt = microtime(1);
for ($i = 0; $i < MAX; ++$i) {
    in_array('key1', $in100);
}
printf('Big in_array() exists near start: %e', microtime(1) - $mt);
echo PHP_EOL;

$mt = microtime(1);
for ($i = 0; $i < MAX; ++$i) {
    in_array('key98', $in100);
}
printf('Big in_array() exists near end: %e', microtime(1) - $mt);
echo PHP_EOL;

$mt = microtime(1);
for ($i = 0; $i < MAX; ++$i) {
    in_array('key', $in100);
}
printf('Big in_array() not exists near end: %e', microtime(1) - $mt);
echo PHP_EOL;