$array1 = array(1,2,3,4,5,6);
$array2 = array(2,3);

//1、獲取陣列鍵值對
$arr1 = array_keys($array2);

var_dump($arr1);

Array
(
    [0] => 0
    [1] => 1
)
        
//2、獲取陣列元素值
$arr2 = array_values($array2);

var_dump($arr2);

Array
(
    [0] => 2
    [1] => 3
)

//3、按照$array2包含的鍵值，刪除陣列$array1中所有的元素 
$arr3 = array_diff($array1,$array2);

var_dump($arr3);

Array
(
    [0] => 1
    [3] => 4
    [4] => 5
    [5] => 6
)

//4、按照$array2包含的值，刪除陣列$array1中所有的元素 
$arr4 = array_diff_key($array1,$array2);   

var_dump($arr4);

Array
(
    [2] => 3
    [3] => 4
    [4] => 5
    [5] => 6
)