array_key_exists vs. isset

arraykeytest.php

<?php

$iterations = 100000;

$value = [
    'one'   => 1, 
    'two'   => 2, 
    'three' => 3,
];

$totals = [
    'isset_true'      => 0,
    'isset_false'     => 0,
    'array_key_true'  => 0,
    'array_key_false' => 0,
];

echo "PHP Version ".phpversion()."\n\n";

echo str_repeat('-', 50)."\n";

//-----------------------------------------------------------------------------

echo "Testing isset over ".number_format($iterations)." iterations:\n\n";

$start = microtime(true);

for ($i = 0; $i < $iterations; $i++) {
    if (isset($value['one'])) {}
}

$end = microtime(true);

$duration = ($end - $start) * 1000;

$totals['isset_true'] += $duration;

echo str_pad('isset true', 35)."{$duration}\n";

$start = microtime(true);

for ($i = 0; $i < $iterations; $i++) {
    if (isset($value['fail'])) {}
}

$end = microtime(true);

$duration = ($end - $start) * 1000;

$totals['isset_false'] += $duration;

echo str_pad('isset false', 35)."{$duration}\n\n";

//-----------------------------------------------------------------------------

echo "Testing array_key_exists over ".number_format($iterations)." iterations:\n\n";

$start = microtime(true);

for ($i = 0; $i < $iterations; $i++) {
    if (array_key_exists('one', $value)) {}
}

$end = microtime(true);

$duration = ($end - $start) * 1000;

$totals['array_key_true'] += $duration;

echo str_pad('array_key_exists true', 35)."{$duration}\n";

$start = microtime(true);

for ($i = 0; $i < $iterations; $i++) {
    if (array_key_exists('fail', $value)) {}
}

$end = microtime(true);

$duration = ($end - $start) * 1000;

$totals['array_key_false'] += $duration;

echo str_pad('array_key_exists false', 35)."{$duration}\n";

//-----------------------------------------------------------------------------

echo "\n".str_repeat('-', 50)."\n";
echo str_pad('', 35);
echo str_pad('total (ms)', 20)."\n";
echo str_repeat('-', 50)."\n";

foreach ($totals as $name => $total) {
    echo str_pad($name, 35);
    echo str_pad($total, 20)."\n";
}

echo "\n";

arraykeytest.txt

PHP Version 5.6.3

--------------------------------------------------
Testing isset over 100,000 iterations:

isset true                         23.11897277832
isset false                        21.745920181274

Testing array_key_exists over 100,000 iterations:

array_key_exists true              95.006942749023
array_key_exists false             88.358879089355

--------------------------------------------------
                                   total (ms)
--------------------------------------------------
isset_true                         23.11897277832
isset_false                        21.745920181274
array_key_true                     95.006942749023
array_key_false                    88.358879089355