Speed test for array_merge() function of PHP.

SpeedTest-array_merge.php

<?php
/**
 * Speed test for array_merge() function of PHP.
 *
 * Tested using PHP 7.0.2 (2016.02.11) for Windows 7.
 *
 * Results are consistent, suggesting that, where the possible outputs from
 * using "array_merge()" versus using the "+" operator aren't different,
 * it may be faster to use the "+" operator (note that, depending on what's
 * being merged, the outputs may sometimes differ).
 */

$arr_test1 = array(
	'a' => 'aaa',
	'b' => 'bbbb',
	'c' => 'ccccc',
	'd' => 'dddddd',
	'e' => 'eeeeeee',
	'f' => 'ffffffff',
	'g' => 'ggggggggg',
	'h' => 'hhhhhhhhhh',
	'i' => 'iiiiiiiiiii',
	'j' => 'jjjjjjjjjjjj',
	0 => 100,
	1 => 200,
	3 => 400,
	4 => 800,
	5 => 1600,
	6 => 3200,
	7 => 6400,
	8 => 12800,
	9 => 25600,
	10 => 51200
);

$arr_test2 = array(
	'k' => 'kkk',
	'l' => 'llll',
	'm' => 'mmmmm',
	'n' => 'nnnnnn',
	'o' => 'ooooooo',
	'p' => 'pppppppp',
	'q' => 'qqqqqqqqq',
	'r' => 'rrrrrrrrrr',
	's' => 'sssssssssss',
	't' => 'tttttttttttt',
	0 => 101,
	1 => 202,
	3 => 404,
	4 => 808,
	5 => 1616,
	6 => 3232,
	7 => 6464,
	8 => 12928,
	9 => 25856,
	10 => 51712
);

$t = microtime();
$x = array();

for($i = 0; $i < 100000; $i++) {
    $x = array_merge($arr_test1, $arr_test2);
}

echo 'Test 1: ' . (microtime() - $t) . ' seconds required.' . "\n\n";

$t = microtime();
$x = array();

for($i = 0; $i < 100000; $i++) {
    $x = $arr_test1 + $arr_test2;
}

echo 'Test 2: ' . (microtime() - $t) . ' seconds required.' . "\n\n";

/**
 * Results:
 *
 * Test 1: 0.0624 seconds required.
 *
 * Test 2: 0.0468 seconds required.
 */