一个数组包含null和其他空值的数组差异问题

我用的是拉威尔。我有两个数组。例如

$array1 = [
    'test1',
    '',
    'test2',
    'test3',
    '',
    'test4',
    '',
];

$array2 = [
    null
];

dd(array_diff($array1, $array2));

结果是

array:4 [▼
  0 => "test1"
  2 => "test2"
  3 => "test3"
  5 => "test4"
]

但我预料到了

array:7 [▼
  0 => "test1"
  1 => ""
  2 => "test2"
  3 => "test3"
  4 => ""
  5 => "test4"
  6 => ""
]

null is equal ''

foreach ($array1 as $key => $value) {
    if (in_array($value, $array2, true)) {
        unset($array1[$key]);
    }
}