[PHP] Calculate all the possible subsets given an array of elements

subsets.php

<?php
/**
* This is a function run recursevly to calculate all the possible subsets given an array
**/
function getAllSubsets($nums, &$result){
	
	for ($i = 0; $i<count($nums); $i++)
	{
		$val = $nums[$i];
		
		
		$result = ($result == " " ? $result.$val : $result." ".$val);
		
		if ($i != 0){
			for ($j=0;$j<=$i; $j++)
			{
				$val = $nums[$j];
				
				if ($j==0){
					$valInner = $val;
				}
				else
				{
					$valInner = $valInner.",".$val;
				}
			}
			$result .= " ".$valInner;
		}
	}
	array_shift($nums);
	if (count($nums) > 0){
		getAllSubsets($nums, $result);
	}
}

$result=" ";
$nums = ['1','2','3', '4'];
getAllSubsets($nums, $result);
print_r (explode(" ", $result));