Eloquent集合 - laravel 5.3 中文文档

# Eloquent: 集合

- [简介](#introduction)
- [可用的方法](#available-methods)
- [自定义集合](#custom-collections)


## 简介

默认情况下 Eloquent 返回的都是一个 `IlluminateDatabaseEloquentCollection` 对象的实例，包含通过 `get` 方法或是访问一个关联来获取到的结果。Eloquent 集合对象继承了 Laravel [集合基类](/docs/{{version}}/collections)，因此它自然也继承了许多可用于与 Eloquent 模型交互的方法。

当然，所有集合都可以作为迭代器，来让你像遍历一个 PHP 数组一样来遍历一个集合：

$users = AppUser::where('active', 1)->get();

foreach ($users as $user) {
echo $user->name;
}

然而，集合比数组更强大的地方是其使用了各种 map / reduce 的直观操作。例如，我们移除所有未激活的用户模型和收集其余各个用户的名字：

$users = AppUser::where('active', 1)->get();

$names = $users->reject(function ($user) {
return $user->active === false;
})
->map(function ($user) {
return $user->name;
});

> {note} 大部分的 Eloquent 集合会返回新的「Eloquent 集合」实例，但是 `pluck`, `keys`, `zip`, `collapse`, `flatten` 和 `flip` 方法会返回 [基础集合](/docs/{{version}}/collections) 实例。
>
> 相应的，如果一个 `map` 操作返回一个不包含任何 Eloquent 模型的集合，那么它将会自动转换成基础集合。



## 可用的方法

### 集合对象

所有 Eloquent 集合都继承了基础的 [Laravel 集合](/docs/{{version}}/collections) 对象。因此，他们也继承了所有集合类提供的强大的方法：


#collection-method-list > p {
column-count: 3; -moz-column-count: 3; -webkit-column-count: 3;
column-gap: 2em; -moz-column-gap: 2em; -webkit-column-gap: 2em;
}

#collection-method-list a {
display: block;
}




[all](/docs/{{version}}/collections#method-all)
[avg](/docs/{{version}}/collections#method-avg)
[chunk](/docs/{{version}}/collections#method-chunk)
[collapse](/docs/{{version}}/collections#method-collapse)
[combine](/docs/{{version}}/collections#method-combine)
[contains](/docs/{{version}}/collections#method-contains)
[count](/docs/{{version}}/collections#method-count)
[diff](/docs/{{version}}/collections#method-diff)
[diffKeys](/docs/{{version}}/collections#method-diffkeys)
[each](/docs/{{version}}/collections#method-each)
[every](/docs/{{version}}/collections#method-every)
[except](/docs/{{version}}/collections#method-except)
[filter](/docs/{{version}}/collections#method-filter)
[first](/docs/{{version}}/collections#method-first)
[flatMap](/docs/{{version}}/collections#method-flatmap)
[flatten](/docs/{{version}}/collections#method-flatten)
[flip](/docs/{{version}}/collections#method-flip)
[forget](/docs/{{version}}/collections#method-forget)
[forPage](/docs/{{version}}/collections#method-forpage)
[get](/docs/{{version}}/collections#method-get)
[groupBy](/docs/{{version}}/collections#method-groupby)
[has](/docs/{{version}}/collections#method-has)
[implode](/docs/{{version}}/collections#method-implode)
[intersect](/docs/{{version}}/collections#method-intersect)
[isEmpty](/docs/{{version}}/collections#method-isempty)
[keyBy](/docs/{{version}}/collections#method-keyby)
[keys](/docs/{{version}}/collections#method-keys)
[last](/docs/{{version}}/collections#method-last)
[map](/docs/{{version}}/collections#method-map)
[max](/docs/{{version}}/collections#method-max)
[merge](/docs/{{version}}/collections#method-merge)
[min](/docs/{{version}}/collections#method-min)
[only](/docs/{{version}}/collections#method-only)
[pluck](/docs/{{version}}/collections#method-pluck)
[pop](/docs/{{version}}/collections#method-pop)
[prepend](/docs/{{version}}/collections#method-prepend)
[pull](/docs/{{version}}/collections#method-pull)
[push](/docs/{{version}}/collections#method-push)
[put](/docs/{{version}}/collections#method-put)
[random](/docs/{{version}}/collections#method-random)
[reduce](/docs/{{version}}/collections#method-reduce)
[reject](/docs/{{version}}/collections#method-reject)
[reverse](/docs/{{version}}/collections#method-reverse)
[search](/docs/{{version}}/collections#method-search)
[shift](/docs/{{version}}/collections#method-shift)
[shuffle](/docs/{{version}}/collections#method-shuffle)
[slice](/docs/{{version}}/collections#method-slice)
[sort](/docs/{{version}}/collections#method-sort)
[sortBy](/docs/{{version}}/collections#method-sortby)
[sortByDesc](/docs/{{version}}/collections#method-sortbydesc)
[splice](/docs/{{version}}/collections#method-splice)
[sum](/docs/{{version}}/collections#method-sum)
[take](/docs/{{version}}/collections#method-take)
[toArray](/docs/{{version}}/collections#method-toarray)
[toJson](/docs/{{version}}/collections#method-tojson)
[transform](/docs/{{version}}/collections#method-transform)
[union](/docs/{{version}}/collections#method-union)
[unique](/docs/{{version}}/collections#method-unique)
[values](/docs/{{version}}/collections#method-values)
[where](/docs/{{version}}/collections#method-where)
[whereStrict](/docs/{{version}}/collections#method-wherestrict)
[whereIn](/docs/{{version}}/collections#method-wherein)
[whereInLoose](/docs/{{version}}/collections#method-whereinloose)
[zip](/docs/{{version}}/collections#method-zip)




## 自定义集合


如果你需要使用一个自定义的 `Collection` 对象到自己的扩充方法上，则可以在模型中重写 `newCollection` 方法：


namespace App;

use AppCustomCollection;
use IlluminateDatabaseEloquentModel;

class User extends Model
{

public function newCollection(array $models = [])
{
return new CustomCollection($models);
}
}


一旦你定义了 `newCollection` 方法，则可在任何 Eloquent 返回该模型的 `Collection` 实例时，接收到一个你的自定义集合的实例。如果你想要在应用程序的每个模型中使用自定义集合，则应该在所有的模型继承的模型基类中重写 `newCollection` 方法。