randomize arrays

randomize.php

<?php

function randomize($initial, $to_merge = NULL)
{
	$result = array();
	$lengths = array();
	$total = 0;
	$arrays = func_get_args();

	foreach ($arrays as $array)
	{
		$count = count($array);
		$total += $count;
		$lengths[] = $count;
	}

	$shuffled = range(0, $total - 1);

	shuffle($shuffled);

	foreach ($shuffled as $number)
	{
		$step = 0;
		foreach ($lengths as $key => $length)
		{
			if ($number < $step + $length)
			{
				$result[] = $arrays[$key][$number - $step];
				break;
			}
			$step += $length;
		}
	}

	return $result;
}