for($h=1;$h<100;$h++)
{ 
       if(!array_key_exists($h, $categories))
        {  
				break;
        }
		
		if (!array_key_exists(1, $categories[$h]))
		    {
				break;
        }
       
        for($i=1;$i<100;$i++)
        { 
                if(!array_key_exists($i, $categories[$h]))
                {  
						break;
                }
				
				//print(sizeof($strings));
			
				
                // This will turn the array into a string with all subcategories, separated by ;.
                // For example, 0;3;53 if subcategory 0, 3 and 53 are checked
                $strings[$h][$i] = implode(';', $categories[$h][$i]);
			 
        }
		
}