[PHP知识库]PHP函数array_udiff

array_udiff通过自定义函数来比较值，计算数组的差集?

/**
 * Computes the difference of arrays by using a callback function for data comparison
 * @link https://php.net/manual/en/function.array-udiff.php
 * @param array $array1 <p>
 * The first array.
 * </p>
 * @param array $array2 <p>
 * The second array.
 * </p>
 * @param array $_ [optional]
 * @param callback $data_compare_func <p>
 * The callback comparison function.
 * </p>
 * <p>
 * The user supplied callback function is used for comparison.
 * It must return an integer less than, equal to, or greater than zero if
 * the first argument is considered to be respectively less than, equal
 * to, or greater than the second.
 * </p>
 * @return array an array containing all the values of array1
 * that are not present in any of the other arguments.
 * @meta
 */
function array_udiff(array $array1, array $array2, array $_ = null, $data_compare_func) { }

?示例：

$array1 = [
    'a' => 'aaa-1',
    'b' => 'bbb-1',
    'c' => 'ccc'
];

$array2 = [
    'a' => 'aaa-2',
    'b' => 'bbb-2',
    'e' => 'ccc'
];

$result = array_udiff($array1, $array2, function($v1, $v2){
    if ($v1 == $v2) {
        return 0;
    }

    return $v1 > $v2 ? 1 : -1;
});

var_dump($result);

//结果
//array(2) {
//  'a' =>
//  string(5) "aaa-1"
//  'b' =>
//  string(5) "bbb-1"
//}