Question

I am looking for an error free code for getting unchanged, added, and removed items array by comparing two array.

Is there any efficient method to obtain three arrays by using a single method ?

both php or javascript can be used

Answer 1

PHP has rich set of array features all you need is array_diff and array_intersect

$i = array("k1","k2","k3","k4","k5");
$l = array("k1","k3","k5","k6");

// Removed
$r = array_diff($i, $l);

// Unchanged
$u = array_intersect($i, $l);

// Added
$a = array_diff($l, $i);

var_dump($r, $u, $a);

Output

array (size=2)
  1 => string 'k2' (length=2)
  3 => string 'k4' (length=2)
array (size=3)
  0 => string 'k1' (length=2)
  2 => string 'k3' (length=2)
  4 => string 'k5' (length=2)
array (size=1)
  3 => string 'k6' (length=2)

You can create your own function

function getSet($l, $r) {
    return array("diff" => array_diff($l, $r),"unchanged" => array_intersect($l, $r),"added" => array_diff($r, $l));
}