PHP 错误。为什么 "variable undefined"在 array_map 里面？

Question

我在我的 php 应用程序中使用 array_map 函数。我这样定义了 array_map 函数。

$ratingID =  $this->db->insert_id();

    $rated_item_array = array_map(function ($a) {
        return $a + array('RatingID' => $ratingID);
    }, $rated_item_array);  

PHP通知来了

A PHP Error was encountered

Severity: Notice

Message: Undefined variable: ratingID

当我打印 $ratingID 时。我正确地打印了值，因此定义了 $ratingID。为什么它在array_map 函数中是未定义的？ 我的 $rated_item_array 是

Array
(
    [0] => Array
        (
            [RatingFactorPreferenceID] => 1,
            [PreferenceID] => 45,
            [RatedValue] => 1,
            [CreatedOn] => 1326790338,
            [CreatedBy] => 25
        )

    [1] => Array
        (
            [RatingFactorPreferenceID] => 2,
            [PreferenceID] => 45,
            [RatedValue] => 1,
            [CreatedOn] => 1326790338,
            [CreatedBy] => 25
        )

    [2] => Array
        (
            [RatingFactorPreferenceID] => 3,
            [PreferenceID] => 45,
            [RatedValue] => 1,
            [CreatedOn] => 1326790338,
            [CreatedBy] => 25
        )
)

Answer 1

$rated_item_array = array_map(
  function ($a) use ($ratingID){ 
    return $a + array('RatingID' => $ratingID ); 
  }, 
  $rated_item_array
);