empty vs array_key_exists

array_key_exists.php

<?php

define('ITERATIONS', 10000000);

$array = array(
    'foo' => 'bar',
    'baz' => 'zzz',
);

for ($i = 0; $i < ITERATIONS; $i++) {
    array_key_exists('foo', $array);
    array_key_exists('invalid', $array);
}

print 'Finished' . PHP_EOL;

empty.php

<?php

define('ITERATIONS', 10000000);

$array = array(
    'foo' => 'bar',
    'baz' => 'zzz',
);

for ($i = 0; $i < ITERATIONS; $i++) {
    empty($array['foo']);
    empty($array['invalid']);
}

print 'Finished' . PHP_EOL;

results.txt

-----------------------------------------------------------------------
⮀ time php array_key_exists.php
Finished
php array_key_exists.php  20.92s user 0.20s system 99% cpu 21.185 total
-----------------------------------------------------------------------
 
-----------------------------------------------------------------------
⮀ time php empty.php
Finished
php empty.php  2.90s user 0.03s system 98% cpu 2.982 total
-----------------------------------------------------------------------

-----------------------------------------------------------------------
⮀ time php empty.php
Finished
php empty.php  2.91s user 0.04s system 98% cpu 2.995 total
-----------------------------------------------------------------------

-----------------------------------------------------------------------
⮀ time php array_key_exists.php
Finished
php array_key_exists.php  19.22s user 0.17s system 99% cpu 19.460 total
-----------------------------------------------------------------------