Question

我有2个数组，$array0和$array1。我们先预先填写它们：

$user01 = array("no" => 1, "name" => "john");
$user02 = array("no" => 2, "name" => "lewis");
$user03 = array("no" => 3, "name" => "dan");

$array0 = array($user01, $user02, $user03, $user04);

$user11 = array("id" => 1, "name" => "john", "attr" => "foo");
$user12 = array("id" => 7, "name" => "mark", "attr" => "bar");

$array1 = array($user11, $user12);

我希望让$array0的所有用户都不在$array1，因此我使用array_udiff：

$diff = array_udiff($array0, $array1, function ($userA, $userB) {
  return $userA['no'] == $userB['id'];
});

但是，在匿名比较功能中，如果我执行var_dump $userA和$userB，它们似乎都属于$array0，而我的行为是期待$userA属于$array0和$userB属于$array1。

即，预期的答案是[[2, "lewis"], [3, "dan"]]，但我在比较函数的行中得到了“未找到的索引”：“未定义的索引id”。

我错过了array_udiff行为的内容吗？

Answer 1

我很确定PHP希望比较函数的参数可以互换，你需要更改数组索引是常见的，或者在比较函数中实现逻辑来处理这个问题。
这不是比较函数的工作原理。

如果第一个参数被认为分别小于，等于或大于第二个参数，则比较函数必须返回小于，等于或大于零的整数。

所以：

$user01 = array("id" => 1, "name" => "john");  // "no" changed to "id"
$user02 = array("id" => 2, "name" => "lewis");
$user03 = array("id" => 3, "name" => "dan");

$array0 = array($user01, $user02, $user03); // non-existant $user04 removed

$user11 = array("id" => 1, "name" => "john", "attr" => "foo");
$user12 = array("id" => 7, "name" => "mark", "attr" => "bar");

$array1 = array($user11, $user12);

$diff = array_udiff($array0, $array1, function ($userA, $userB) {
    if( $userA['id'] == $userB['id'] ) { return 0; }  // compare function re-jiggered
    else { return $userA['id'] - $userB['id']; }
});

print_r($diff);

收率：

Array
(
    [1] => Array
        (
            [id] => 2
            [name] => lewis
        )

    [2] => Array
        (
            [id] => 3
            [name] => dan
        )

)

PHP array_udiff奇怪的行为

1 个答案: