phparraysarray-intersect

Array Intersection - only once


Newbie here, so I have a problem with the array_intersect function. I am comparing two arrays with intersection but I get some results twice. For example: 2 arrays

$array1 = array(apple, orange, orange, apricot, melon, watermelon);
$array2 = array(apple, orange);

$result = array_intersect($array1, $array2); This returns:

$result = array(apple, orange, orange);

But I want this:

$result = array(apple, orange);

I want this to return apple and orange ONCE each. Currently it returns apple, then orange, and then another orange. Am I missing something or am I simply using the wrong function.

edit: Based on the answers I have to clarify this. If the 2nd array is

$array1 = array(apple, orange, orange, apricot, melon, watermelon);
$array2 = array(apple, orange, orange);

I want the result to have 2 oranges, so array_unique wont do it.

$result = array(apple, orange, orange);

Solution

  • Loop through first array. If second array has value put it to result and remove from second array.

    $array1 = array('apple', 'orange', 'orange', 'apricot', 'melon', 'watermelon');
    $array2 = array('apple', 'orange');
    $array3 = array('apple', 'orange', 'orange');
    
    function my_intersect($array1, $array2)
        {
        // array_walk($array1, 'sort');
        // array_walk($array2, 'sort');
        return array_filter($array1, function($item)use(&$array2)
            {
            if (($key = array_search($item, $array2)) !== false)
                {
                unset($array2[$key]);
                return true;
                }
            return false;
            });
        }
    
    var_dump(my_intersect($array1, $array2)); // 'apple', 'orange'
    var_dump(my_intersect($array1, $array3)); // 'apple', 'orange', 'orange'