Eloquent 集合 · laravel 5.4

<article><h1>Eloquent: 集合</h1><ul><li><a href="#introduction">簡介</a></li><li><a href="#available-methods">可用的方法</a></li><li><a href="#custom-collections">自定義集合</a></li></ul><a name="introduction"></a><h2><a href="#introduction">簡介</a></h2>默認情況下 Eloquent 返回的都是一個 <code class=" language-php">Illuminate\Database\Eloquent\Collection</code> 對象的實例，包含通過 <code class=" language-php">get</code> 方法或是訪問一個關聯來獲取到的結果。Eloquent 集合對象繼承了 Laravel <a href="/docs/5.4/collections">集合基類</a>，因此它自然也繼承了許多可用于與 Eloquent 模型交互的方法。當然，所有集合都可以作為迭代器，來讓你像遍歷一個 PHP 數組一樣來遍歷一個集合：<pre class=" language-php"><code class=" language-php">$users = App\User::where('active', 1)->get(); foreach ($users as $user) { echo $user->name; }</code></pre>然而，集合比數組更強大的地方是其使用了各種 map / reduce 的直觀操作。例如，我們移除所有未激活的用戶模型和收集其余各個用戶的名字：<pre class=" language-php"><code class=" language-php">$users = App\User::where('active', 1)->get(); $names = $users->reject(function ($user) { return $user->active === false; }) ->map(function ($user) { return $user->name; });</code></pre><blockquote class="has-icon note"><div class="flag"><svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:a="http://ns.adobe.com/AdobeSVGViewerExtensions/3.0/" version="1.1" x="0px" y="0px" width="90px" height="90px" viewBox="0 0 90 90" enable-background="new 0 0 90 90" xml:space="preserve"><path fill="#FFFFFF" d="M45 0C20.1 0 0 20.1 0 45s20.1 45 45 45 45-20.1 45-45S69.9 0 45 0zM45 74.5c-3.6 0-6.5-2.9-6.5-6.5s2.9-6.5 6.5-6.5 6.5 2.9 6.5 6.5S48.6 74.5 45 74.5zM52.1 23.9l-2.5 29.6c0 2.5-2.1 4.6-4.6 4.6 -2.5 0-4.6-2.1-4.6-4.6l-2.5-29.6c-0.1-0.4-0.1-0.7-0.1-1.1 0-4 3.2-7.2 7.2-7.2 4 0 7.2 3.2 7.2 7.2C52.2 23.1 52.2 23.5 52.1 23.9z"></path></svg></div> 大部分的 Eloquent 集合會返回新的「Eloquent 集合」實例，但是 <code class=" language-php">pluck</code>, <code class=" language-php">keys</code>, <code class=" language-php">zip</code>, <code class=" language-php">collapse</code>, <code class=" language-php">flatten</code> 和 <code class=" language-php">flip</code> 方法會返回 <a href="/docs/5.4/collections">基礎集合</a> 實例。相應的，如果一個 <code class=" language-php">map</code> 操作返回一個不包含任何 Eloquent 模型的集合，那么它將會自動轉換成基礎集合。</blockquote><a name="available-methods"></a><h2><a href="#available-methods">可用的方法</a></h2><h3>集合對象</h3>所有 Eloquent 集合都繼承了基礎的 <a href="/docs/5.4/collections">Laravel 集合</a> 對象。因此，他們也繼承了所有集合類提供的強大的方法：<style>#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; }</style><div id="collection-method-list"><a href="/docs/5.4/collections#method-all">all</a> <a href="/docs/5.4/collections#method-avg">avg</a> <a href="/docs/5.4/collections#method-chunk">chunk</a> <a href="/docs/5.4/collections#method-collapse">collapse</a> <a href="/docs/5.4/collections#method-combine">combine</a> <a href="/docs/5.4/collections#method-contains">contains</a> <a href="/docs/5.4/collections#method-count">count</a> <a href="/docs/5.4/collections#method-diff">diff</a> <a href="/docs/5.4/collections#method-diffkeys">diffKeys</a> <a href="/docs/5.4/collections#method-each">each</a> <a href="/docs/5.4/collections#method-every">every</a> <a href="/docs/5.4/collections#method-except">except</a> <a href="/docs/5.4/collections#method-filter">filter</a> <a href="/docs/5.4/collections#method-first">first</a> <a href="/docs/5.4/collections#method-flatmap">flatMap</a> <a href="/docs/5.4/collections#method-flatten">flatten</a> <a href="/docs/5.4/collections#method-flip">flip</a> <a href="/docs/5.4/collections#method-forget">forget</a> <a href="/docs/5.4/collections#method-forpage">forPage</a> <a href="/docs/5.4/collections#method-get">get</a> <a href="/docs/5.4/collections#method-groupby">groupBy</a> <a href="/docs/5.4/collections#method-has">has</a> <a href="/docs/5.4/collections#method-implode">implode</a> <a href="/docs/5.4/collections#method-intersect">intersect</a> <a href="/docs/5.4/collections#method-isempty">isEmpty</a> <a href="/docs/5.4/collections#method-keyby">keyBy</a> <a href="/docs/5.4/collections#method-keys">keys</a> <a href="/docs/5.4/collections#method-last">last</a> <a href="/docs/5.4/collections#method-map">map</a> <a href="/docs/5.4/collections#method-max">max</a> <a href="/docs/5.4/collections#method-merge">merge</a> <a href="/docs/5.4/collections#method-min">min</a> <a href="/docs/5.4/collections#method-only">only</a> <a href="/docs/5.4/collections#method-pluck">pluck</a> <a href="/docs/5.4/collections#method-pop">pop</a> <a href="/docs/5.4/collections#method-prepend">prepend</a> <a href="/docs/5.4/collections#method-pull">pull</a> <a href="/docs/5.4/collections#method-push">push</a> <a href="/docs/5.4/collections#method-put">put</a> <a href="/docs/5.4/collections#method-random">random</a> <a href="/docs/5.4/collections#method-reduce">reduce</a> <a href="/docs/5.4/collections#method-reject">reject</a> <a href="/docs/5.4/collections#method-reverse">reverse</a> <a href="/docs/5.4/collections#method-search">search</a> <a href="/docs/5.4/collections#method-shift">shift</a> <a href="/docs/5.4/collections#method-shuffle">shuffle</a> <a href="/docs/5.4/collections#method-slice">slice</a> <a href="/docs/5.4/collections#method-sort">sort</a> <a href="/docs/5.4/collections#method-sortby">sortBy</a> <a href="/docs/5.4/collections#method-sortbydesc">sortByDesc</a> <a href="/docs/5.4/collections#method-splice">splice</a> <a href="/docs/5.4/collections#method-sum">sum</a> <a href="/docs/5.4/collections#method-take">take</a> <a href="/docs/5.4/collections#method-toarray">toArray</a> <a href="/docs/5.4/collections#method-tojson">toJson</a> <a href="/docs/5.4/collections#method-transform">transform</a> <a href="/docs/5.4/collections#method-union">union</a> <a href="/docs/5.4/collections#method-unique">unique</a> <a href="/docs/5.4/collections#method-values">values</a> <a href="/docs/5.4/collections#method-where">where</a> <a href="/docs/5.4/collections#method-wherestrict">whereStrict</a> <a href="/docs/5.4/collections#method-wherein">whereIn</a> <a href="/docs/5.4/collections#method-whereinloose">whereInLoose</a> <a href="/docs/5.4/collections#method-zip">zip</a></div><a name="custom-collections"></a><h2><a href="#custom-collections">自定義集合</a></h2>如果你需要使用一個自定義的 <code class=" language-php">Collection</code> 對象到自己的擴充方法上，則可以在模型中重寫 <code class=" language-php">newCollection</code> 方法：<pre class=" language-php"><code class=" language-php"><?php namespace App; use App\CustomCollection; use Illuminate\Database\Eloquent\Model; class User extends Model { /** * 創建一個新的 Eloquent 集合實例對象。 * * @param array $models * @return \Illuminate\Database\Eloquent\Collection */ public function newCollection(array $models = []) { return new CustomCollection($models); } }</code></pre>一旦你定義了 <code class=" language-php">newCollection</code> 方法，則可在任何 Eloquent 返回該模型的 <code class=" language-php">Collection</code> 實例時，接收到一個你的自定義集合的實例。如果你想要在應用程序的每個模型中使用自定義集合，則應該在所有的模型繼承的模型基類中重寫 <code class=" language-php">newCollection</code> 方法。<h2>譯者署名</h2><table><thead><tr><th>用戶名</th><th>頭像</th><th>職能</th><th>簽名</th></tr></thead><tbody><tr><td><a href="https://laravel-china.org/users/79">@skyverd</a></td><td><img class="avatar-66 rm-style" src="https://dn-phphub.qbox.me/uploads/avatars/79_1427370664.jpeg?imageView2/1/w/100/h/100"></td><td>翻譯</td><td>全桟工程師，<a href="https://skyverd.com">時光博客</a></td></tr></tbody></table></article>