Compare 2 similar arrays and remove all similar items in the beginning-CodePudding

I have 2 similar arrays:

  $array_a = array(
    array(
      "id" => 1,
      "merchant_reference" => "12345"
    ),
    array(
      "id" => 2,
      "merchant_reference" => "67890"
    )
  );

  $array_b = array(
    array(
      "id" => 1,
      "merchant_reference" => "12345"
    ),
    array(
      "id" => 2,
      "merchant_reference" => "67890"
    ),
    array(
      "id" => 3,
      "merchant_reference" => "12345"
    )
  );

The only difference is $array_b has an additional item. I'd like to output a new array that counts the total keys of $array_a and removes all keys in $array_b up to that count. And, just leave the 3rd item in $array_b.

I've tried:

function compare_arrays($array1, $array2) {
    $array1_count = count($array1);
    $array2_count = count($array2);
    $array2_count = $array2_count - $array1_count;
    $array2 = array_slice($array2, $array1_count, $array2_count);

    return $array2;
}

But, what's the best way to do this?

CodePudding user response：

As per the discussion under comment, your code is fine, just an additional conditional check which will improve execution time in case no addition after 12 pm is found.

function compare_arrays($array1, $array2) {
    $array1_count = count($array1);
    $array2_count = count($array2);
    $array2_count = $array2_count - $array1_count;
    if($array2_count > 0){
        return $array2 = array_slice($array2, $array1_count, $array2_count);
    }
    return $array1;
}