array_diff_key() vs. loop/unset

arraydifftest

PHP Version 5.4.30

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Testing 10 item array over 1,000 iterations:

array_diff_key                          1.2109279632568
loop/unset                              0.87404251098633
-------------------------------------------------------
Testing 100 item array over 1,000 iterations:

array_diff_key                          2.9680728912354
loop/unset                              6.4740180969238
-------------------------------------------------------
Testing 1,000 item array over 1,000 iterations:

array_diff_key                          18.290042877197
loop/unset                              62.99090385437
-------------------------------------------------------
Testing 10,000 item array over 1,000 iterations:

array_diff_key                          247.08890914917
loop/unset                              610.44406890869
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Testing 50,000 item array over 1,000 iterations:

array_diff_key                          1920.4831123352
loop/unset                              3059.1459274292
-------------------------------------------------------
Testing 100,000 item array over 1,000 iterations:

array_diff_key                          4492.7201271057
loop/unset                              6168.4861183167

-------------------------------------------------------
                    average (ms)        total (ms)
-------------------------------------------------------
array_diff_key      1113.7935320536     6682.7611923218
loop/unset          1651.4025131861     9908.4150791168

arraydifftest.php

<?php

$iterations = 1000;

$sizes = [10, 100, 1000, 10000, 50000, 100000];

$totals = [
    'array_diff_key' => 0,
    'loop/unset'     => 0,
];

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

foreach ($sizes as $size) {
    $source = array_fill(0, $size, true);
    $test   = array_filter($source, function($val) {
        static $count = 0;

        $count++;

        return 0 === $count % 2;
    });

    echo str_repeat('-', 55)."\n";

    echo "Testing ".number_format($size)." item array over ".number_format($iterations)." iterations:\n\n";

    // -- array_diff_key ------------------------------------------------------

    $out = $source;

    $start = microtime(true);

    for ($i = 0; $i < $iterations; $i++) {
        $out = array_diff_key($out, $test);
    }

    $end = microtime(true);

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

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

    echo str_pad("array_diff_key", 40)."{$duration}\n";

    // -- loop/unset ----------------------------------------------------------

    $out = $source;

    $start = microtime(true);

    for ($i = 0; $i < $iterations; $i++) {
        foreach ($test as $key => $val) {
            unset($out[$key]);
        }
    }

    $end = microtime(true);

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

    $totals['loop/unset'] += $duration;

    echo str_pad("loop/unset", 40)."{$duration}\n";
}

echo "\n".str_repeat('-', 55)."\n";
echo str_pad('', 20);
echo str_pad('average (ms)', 20);
echo str_pad('total (ms)', 20)."\n";
echo str_repeat('-', 55)."\n";

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

echo "\n";