<?php

$elements = [];
for($i = 0; $i < 100000; $i++) {
	$elements[] = (string)rand(10000000, PHP_INT_MAX);
}

function testArrayWalk($array) {
    $time_start = microtime(true);
    $element = array_walk($array, 'test_walking');
    
    $time_end = microtime(true);

	return $time_end - $time_start;
}

function test_walking(&$item1) {
    $item1 = $item1 * 2;
}

function testForeach($array) {
    $time_start = microtime(true);
    foreach ($array as $key => $value) {
        $element[$key] = $value * 2;
    }
    
    $time_end = microtime(true);

	return $time_end - $time_start;
    //return $element;
}

	echo "Array walk took: " . number_format(testArrayWalk($elements) * 1000, 3) . "ms\n";
	echo "Foreach took: " . number_format(testForeach($elements) * 1000, 3) . "ms\n";