iterator_apply() と foreach の比較

iterator_apply_and_foreach.php

<?php
// modified the code from https://gist.github.com/1287753
// see also: https://github.com/zendframework/zf2/pull/502
//
// the result on my Macbook Pro
//
// foreach       : 1.3991289138794
// array_map     : 1.8903770446777
// iterator_apply: 4.6320548057556

ini_set('max_execution_time', 900);

function timer(callback $block) {
    $start = microtime(true);
    for ($i = 0; $i < 100000; ++$i) {
        $block();
    }
    $end = microtime(true);
    return $end - $start;
}

$data = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9];
$iterator = new ArrayIterator($data);
    
$foreachTime = timer(function() use ($data) {
    $result = [];
    foreach ($data as $key => $value) {
        $result[$key] = $value * 2;
    }
});

$mapTime = timer(function() use ($data) {
    $result = [];
    $result = array_map(function ($value) { return $value * 2; }, $data);
});

$iteratorTime = timer(function() use ($data, $iterator) {
    $result = [];
    iterator_apply($iterator, function() use ($result, $iterator) {
        $result[$iterator->key()] = $iterator->current() * 2;
        return true;
    });
});

printf('foreach       : %s' . PHP_EOL, $foreachTime);
printf('array_map     : %s' . PHP_EOL, $mapTime);
printf('iterator_apply: %s' . PHP_EOL, $iteratorTime);