我从我的数据库中加载了一个模型和belongsToMany关系：
$author = Author::with('publications')->first();
/** Returns something like:
{
"id": 3457,
"email": "alex@trump.edu",
"publications": {
"1": {
"id": 240897,
"title": "Food left by other people at a restaurant - is it safe to eat? A comparative review.",
"journal": "Journal of Scrounging and Gleaning",
"year": 2007,
"pivot": {
"author_id": 3457,
"publication_id": 240897
}
},
"2": {
"id": 249196,
"title": "Stop picking at it - you'll leave a scar!",
"journal": "Proceedings of the International Conference on Nagging",
"year": 2008,
"pivot": {
"author_id": 3457,
"publication_id": 249196
}
}
}
}
*/
然后，我从第三方API获取每个publication的一些额外数据，并将其合并到我的集合中，这可以正常工作。
但是，我想根据这个第三方数据对出版物进行排序，因此我在sortByDesc中使用回调：
$sorted = $author->publications->sortByDesc(function ($publication, $key) {
// Blah blah blah not important how I sort
return $blah;
});
$author->publications = $sorted->values();
根据sortBy的文档，如果我想在排序后重新编号我的结果，我需要使用values。 $sorted->values()确实似乎是一个重新键入的排序列表，但即使我将其分配给$author->publications，$author->publications仍然有旧密钥。
更奇怪的是，即使我没有将结果分配回sortByDesc，只运行$author->publications似乎就地对列表进行排序。为什么我不能将重新加密的集合分配回$author->publications？我觉得这与关系与属性的细微差别有关，但我不知道如何解决这个问题。
答案 0 :(得分：1)
问题在于，当我将已排序的集合分配给$author->publication时，我实际上并没有覆盖关系 $author->publication。相反，我只是将新的属性添加到$author，这恰好也称为publication。因此，我的$author对象最终看起来像这样：
UserFrosting\Author Object
(
[timestamps] =>
[connection:protected] =>
[table:protected] => author
[primaryKey:protected] => id
[perPage:protected] => 15
[incrementing] => 1
[attributes:protected] => Array
(
[id] => 3457
[email] => alex@trump.edu
[publications] => Illuminate\Database\Eloquent\Collection Object
(
[items:protected] => Array
(
[0] => UserFrosting\Publication Object
(
[timestamps] =>
[connection:protected] =>
[table:protected] => publication
[primaryKey:protected] => id
[perPage:protected] => 15
[incrementing] => 1
[attributes:protected] => Array
(
[id] => 240897
[title] => Food left by other people at a restaurant - is it safe to eat? A comparative review.
[journal] => Journal of Scrounging and Gleaning
[year] => 2007
)
)
[1] => UserFrosting\Publication Object
(
[timestamps] =>
[connection:protected] =>
[table:protected] => publication
[primaryKey:protected] => id
[perPage:protected] => 15
[incrementing] => 1
[attributes:protected] => Array
(
[id] => 249196
[title] => Stop picking at it - you'll leave a scar!
[journal] => Proceedings of the International Conference on Nagging
[year] => 2008
)
)
)
)
)
[relations:protected] => Array
(
[publications] => Illuminate\Database\Eloquent\Collection Object
(
[items:protected] => Array
(
[1] => UserFrosting\Publication Object
(
[timestamps] =>
[connection:protected] =>
[table:protected] => publication
[primaryKey:protected] => id
[perPage:protected] => 15
[incrementing] => 1
[attributes:protected] => Array
(
[id] => 240897
[title] => Food left by other people at a restaurant - is it safe to eat? A comparative review.
[journal] => Journal of Scrounging and Gleaning
[year] => 2007
)
)
[0] => UserFrosting\Publication Object
(
[timestamps] =>
[connection:protected] =>
[table:protected] => publication
[primaryKey:protected] => id
[perPage:protected] => 15
[incrementing] => 1
[attributes:protected] => Array
(
[id] => 249196
[title] => Stop picking at it - you'll leave a scar!
[journal] => Proceedings of the International Conference on Nagging
[year] => 2008
)
)
)
)
)
)
如您所见，relations包含已排序的发布列表，但仍保留原始密钥。 attributes包含已排序的和重新编号的列表。当我调用$author->toArray()时，它显然使用 relation 而不是属性。因此，诀窍是强迫Eloquent assign my renumbered collection to the relation：
$author->setRelation('publications', $sorted->values());