集合 · laravel 5.4

<article><h1>Laravel 的集合 Collection</h1><ul><li><a href="#introduction">简介</a><ul><li><a href="#creating-collections">创建集合</a></li></ul></li><li><a href="#available-methods">可用的方法</a></li><li><a href="#higher-order-messages">高阶信息传递</a></li></ul><a name="introduction"></a><h2><a href="#introduction">简介</a></h2><code class=" language-php">Illuminate\Support\Collection</code> 类提供一个流畅、便利的封装来操控数组数据。如下面的示例代码，我们用 <code class=" language-php">collect</code> 函数从数组中创建新的集合实例，对每一个元素运行 <code class=" language-php">strtoupper</code> 函数，然后移除所有的空元素：<pre class=" language-php"><code class=" language-php">$collection = collect(['taylor', 'abigail', null])->map(function ($name) { return strtoupper($name); }) ->reject(function ($name) { return empty($name); });</code></pre>如上面的代码示例，<code class=" language-php">Collection</code> 类支持链式调用，一般来说，每一个 <code class=" language-php">Collection</code> 方法会返回一个全新的 <code class=" language-php">Collection</code> 实例，你可以放心地进行链接调用。<a name="creating-collections"></a><h3>创建集合</h3>如上所述，<code class=" language-php">collect</code> 辅助函数会利用传入的数组生成一个新的 <code class=" language-php">Illuminate\Support\Collection</code> 实例。所以要创建一个集合就这么简单：<pre class=" language-php"><code class=" language-php">$collection = collect([1, 2, 3]);</code></pre><blockquote class="has-icon tip"><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="56.6px" height="87.5px" viewBox="0 0 56.6 87.5" enable-background="new 0 0 56.6 87.5" xml:space="preserve"><path fill="#FFFFFF" d="M28.7 64.5c-1.4 0-2.5-1.1-2.5-2.5v-5.7 -5V41c0-1.4 1.1-2.5 2.5-2.5s2.5 1.1 2.5 2.5v10.1 5 5.8C31.2 63.4 30.1 64.5 28.7 64.5zM26.4 0.1C11.9 1 0.3 13.1 0 27.7c-0.1 7.9 3 15.2 8.2 20.4 0.5 0.5 0.8 1 1 1.7l3.1 13.1c0.3 1.1 1.3 1.9 2.4 1.9 0.3 0 0.7-0.1 1.1-0.2 1.1-0.5 1.6-1.8 1.4-3l-2-8.4 -0.4-1.8c-0.7-2.9-2-5.7-4-8 -1-1.2-2-2.5-2.7-3.9C5.8 35.3 4.7 30.3 5.4 25 6.7 14.5 15.2 6.3 25.6 5.1c13.9-1.5 25.8 9.4 25.8 23 0 4.1-1.1 7.9-2.9 11.2 -0.8 1.4-1.7 2.7-2.7 3.9 -2 2.3-3.3 5-4 8L41.4 53l-2 8.4c-0.3 1.2 0.3 2.5 1.4 3 0.3 0.2 0.7 0.2 1.1 0.2 1.1 0 2.2-0.8 2.4-1.9l3.1-13.1c0.2-0.6 0.5-1.2 1-1.7 5-5.1 8.2-12.1 8.2-19.8C56.4 12 42.8-1 26.4 0.1zM43.7 69.6c0 0.5-0.1 0.9-0.3 1.3 -0.4 0.8-0.7 1.6-0.9 2.5 -0.7 3-2 8.6-2 8.6 -1.3 3.2-4.4 5.5-7.9 5.5h-4.1H28h-0.5 -3.6c-3.5 0-6.7-2.4-7.9-5.7l-0.1-0.4 -1.8-7.8c-0.4-1.1-0.8-2.1-1.2-3.1 -0.1-0.3-0.2-0.5-0.2-0.9 0.1-1.3 1.3-2.1 2.6-2.1H41C42.4 67.5 43.6 68.2 43.7 69.6zM37.7 72.5H26.9c-4.2 0-7.2 3.9-6.3 7.9 0.6 1.3 1.8 2.1 3.2 2.1h4.1 0.5 0.5 3.6c1.4 0 2.7-0.8 3.2-2.1L37.7 72.5z"></path></svg></div> 默认 <a href="/docs/5.4/eloquent">Eloquent</a> 模型的查询结果总是以 <code class=" language-php">Collection</code> 实例返回。</blockquote><a name="available-methods"></a><h2><a href="#available-methods">可用的方法</a></h2>接下来，我们将会探讨 <code class=" language-php">Collection</code> 类的所有方法。要记得的是，所有方法都支持链式调用，几乎所有的方法都会返回新的 <code class=" language-php">Collection</code> 实例，让你保留原版的集合以备不时之需。<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="#method-all">all</a> <a href="#method-avg">avg</a> <a href="#method-chunk">chunk</a> <a href="#method-collapse">collapse</a> <a href="#method-combine">combine</a> <a href="#method-contains">contains</a> <a href="#method-count">count</a> <a href="#method-diff">diff</a> <a href="#method-diffkeys">diffKeys</a> <a href="#method-each">each</a> <a href="#method-every">every</a> <a href="#method-except">except</a> <a href="#method-filter">filter</a> <a href="#method-first">first</a> <a href="#method-flatmap">flatMap</a> <a href="#method-flatten">flatten</a> <a href="#method-flip">flip</a> <a href="#method-forget">forget</a> <a href="#method-forpage">forPage</a> <a href="#method-get">get</a> <a href="#method-groupby">groupBy</a> <a href="#method-has">has</a> <a href="#method-implode">implode</a> <a href="#method-intersect">intersect</a> <a href="#method-isempty">isEmpty</a> <a href="#method-keyby">keyBy</a> <a href="#method-keys">keys</a> <a href="#method-last">last</a> <a href="#method-map">map</a> <a href="#method-mapwithkeys">mapWithKeys</a> <a href="#method-max">max</a> <a href="#method-merge">merge</a> <a href="#method-min">min</a> <a href="#method-nth">nth</a> <a href="#method-only">only</a> <a href="#method-partition">partition</a> <a href="#method-pipe">pipe</a> <a href="#method-pluck">pluck</a> <a href="#method-pop">pop</a> <a href="#method-prepend">prepend</a> <a href="#method-pull">pull</a> <a href="#method-push">push</a> <a href="#method-put">put</a> <a href="#method-random">random</a> <a href="#method-reduce">reduce</a> <a href="#method-reject">reject</a> <a href="#method-reverse">reverse</a> <a href="#method-search">search</a> <a href="#method-shift">shift</a> <a href="#method-shuffle">shuffle</a> <a href="#method-slice">slice</a> <a href="#method-sort">sort</a> <a href="#method-sortby">sortBy</a> <a href="#method-sortbydesc">sortByDesc</a> <a href="#method-splice">splice</a> <a href="#method-split">split</a> <a href="#method-sum">sum</a> <a href="#method-take">take</a> <a href="#method-toarray">toArray</a> <a href="#method-tojson">toJson</a> <a href="#method-transform">transform</a> <a href="#method-union">union</a> <a href="#method-unique">unique</a> <a href="#method-values">values</a> <a href="#method-when">when</a> <a href="#method-where">where</a> <a href="#method-wherestrict">whereStrict</a> <a href="#method-wherein">whereIn</a> <a href="#method-whereinstrict">whereInStrict</a> <a href="#method-zip">zip</a></div><a name="method-listing"></a><h2><a href="#method-listing">方法清单</a></h2><style>#collection-method code { font-size: 14px; } #collection-method:not(.first-collection-method) { margin-top: 50px; }</style><a name="method-all"></a><h4 id="collection-method" class="first-collection-method"><code class=" language-php">all()</code></h4>返回该集合所代表的底层 <code class=" language-php">数组</code>：<pre class=" language-php"><code class=" language-php">collect([1, 2, 3])->all(); // [1, 2, 3]</code></pre><a name="method-avg"></a><h4 id="collection-method"><code class=" language-php">avg()</code></h4>返回集合中所有项目的平均值：<pre class=" language-php"><code class=" language-php">collect([1, 2, 3, 4, 5])->avg(); // 3</code></pre>如果集合包含了嵌套数组或对象，你可以通过传递「键」来指定使用哪些值计算平均值：<pre class=" language-php"><code class=" language-php">$collection = collect([ ['name' => 'JavaScript: The Good Parts', 'pages' => 176], ['name' => 'JavaScript: The Definitive Guide', 'pages' => 1096], ]); $collection->avg('pages'); // 636</code></pre><a name="method-chunk"></a><h4 id="collection-method"><code class=" language-php">chunk()</code></h4>将集合拆成多个指定大小的较小集合：<pre class=" language-php"><code class=" language-php">$collection = collect([1, 2, 3, 4, 5, 6, 7]); $chunks = $collection->chunk(4); $chunks->toArray(); // [[1, 2, 3, 4], [5, 6, 7]]</code></pre>这个方法在适用于网格系统如 <a href="http://getbootstrap.com/css/#grid">Bootstrap</a> 的 <a href="/docs/5.4/views">视图</a> 。想像你有一个 <a href="/docs/5.4/eloquent">Eloquent</a> 模型的集合要显示在一个网格内：<pre class=" language-php"><code class=" language-php">@foreach ($products->chunk(3) as $chunk) <div class="row"> @foreach ($chunk as $product) <div class="col-xs-4">{{ $product->name }}</div> @endforeach </div> @endforeach</code></pre><a name="method-collapse"></a><h4 id="collection-method"><code class=" language-php">collapse()</code></h4>将多个数组组成的集合合成单个一维数组集合：<pre class=" language-php"><code class=" language-php">$collection = collect([[1, 2, 3], [4, 5, 6], [7, 8, 9]]); $collapsed = $collection->collapse(); $collapsed->all(); // [1, 2, 3, 4, 5, 6, 7, 8, 9]</code></pre><a name="method-combine"></a><h4 id="collection-method"><code class=" language-php">combine()</code></h4>将集合的值作为「键」，合并另一个数组或者集合作为「键」对应的值。<pre class=" language-php"><code class=" language-php">$collection = collect(['name', 'age']); $combined = $collection->combine(['George', 29]); $combined->all(); // ['name' => 'George', 'age' => 29]</code></pre><a name="method-contains"></a><h4 id="collection-method"><code class=" language-php">contains()</code></h4>判断集合是否含有指定项目：<pre class=" language-php"><code class=" language-php">$collection = collect(['name' => 'Desk', 'price' => 100]); $collection->contains('Desk'); // true $collection->contains('New York'); // false</code></pre>你可以将一对键/值传入 <code class=" language-php">contains</code> 方法，用来判断该组合是否存在于集合内：<pre class=" language-php"><code class=" language-php">$collection = collect([ ['product' => 'Desk', 'price' => 200], ['product' => 'Chair', 'price' => 100], ]); $collection->contains('product', 'Bookcase'); // false</code></pre>最后，你也可以传入一个回调函数到 <code class=" language-php">contains</code> 方法内运行你自己的判断语句：<pre class=" language-php"><code class=" language-php">$collection = collect([1, 2, 3, 4, 5]); $collection->contains(function ($value, $key) { return $value > 5; }); // false</code></pre><a name="method-count"></a><h4 id="collection-method"><code class=" language-php">count()</code></h4>返回该集合内的项目总数：<pre class=" language-php"><code class=" language-php">$collection = collect([1, 2, 3, 4]); $collection->count(); // 4</code></pre><a name="method-diff"></a><h4 id="collection-method"><code class=" language-php">diff()</code></h4>将集合与其它集合或纯 PHP <code class=" language-php">数组</code> 进行值的比较，返回第一个集合中存在而第二个集合中不存在的值：<pre class=" language-php"><code class=" language-php">$collection = collect([1, 2, 3, 4, 5]); $diff = $collection->diff([2, 4, 6, 8]); $diff->all(); // [1, 3, 5]</code></pre><a name="method-diffkeys"></a><h4 id="collection-method"><code class=" language-php">diffKeys()</code></h4>将集合与其它集合或纯 PHP <code class=" language-php">数组</code> 的「键」进行比较，返回第一个集合中存在而第二个集合中不存在「键」所对应的键值对：<pre class=" language-php"><code class=" language-php">$collection = collect([ 'one' => 10, 'two' => 20, 'three' => 30, 'four' => 40, 'five' => 50, ]); $diff = $collection->diffKeys([ 'two' => 2, 'four' => 4, 'six' => 6, 'eight' => 8, ]); $diff->all(); // ['one' => 10, 'three' => 30, 'five' => 50]</code></pre><a name="method-each"></a><h4 id="collection-method"><code class=" language-php">each()</code></h4>遍历集合中的项目，并将之传入回调函数：<pre class=" language-php"><code class=" language-php">$collection = $collection->each(function ($item, $key) { // });</code></pre>回调函数中返回 <code class=" language-php">false</code> 以中断循环：<pre class=" language-php"><code class=" language-php">$collection = $collection->each(function ($item, $key) { if (/* some condition */) { return false; } });</code></pre><a name="method-every"></a><h4 id="collection-method"><code class=" language-php">every()</code></h4>判断集合中每一个元素是否都符合指定条件：<pre class=" language-php"><code class=" language-php">collect([1, 2, 3, 4])->every(function ($value, $key) { return $value > 2; }); // false</code></pre><a name="method-except"></a><h4 id="collection-method"><code class=" language-php">except()</code></h4>返回集合中除了指定键以外的所有项目：<pre class=" language-php"><code class=" language-php">$collection = collect(['product_id' => 1, 'price' => 100, 'discount' => false]); $filtered = $collection->except(['price', 'discount']); $filtered->all(); // ['product_id' => 1]</code></pre>与 <code class=" language-php">except</code> 相反的方法请查看 <a href="#method-only">only</a>。<a name="method-filter"></a><h4 id="collection-method"><code class=" language-php">filter()</code></h4>使用回调函数筛选集合，只留下那些通过判断测试的项目：<pre class=" language-php"><code class=" language-php">$collection = collect([1, 2, 3, 4]); $filtered = $collection->filter(function ($value, $key) { return $value > 2; }); $filtered->all(); // [3, 4]</code></pre>如果没有提供回调函数，集合中所有返回 <code class=" language-php">false</code> 的元素都会被移除：<pre class=" language-php"><code class=" language-php">$collection = collect([1, 2, 3, null, false, '', 0, []]); $collection->filter()->all(); // [1, 2, 3]</code></pre>与 <code class=" language-php">filter</code> 相反的方法可以查看 <a href="#method-reject">reject</a>。<a name="method-first"></a><h4 id="collection-method"><code class=" language-php">first()</code></h4>返回集合第一个通过指定测试的元素：<pre class=" language-php"><code class=" language-php">collect([1, 2, 3, 4])->first(function ($value, $key) { return $value > 2; }); // 3</code></pre>你也可以不传入参数使用 <code class=" language-php">first</code> 方法以获取集合中第一个元素。如果集合是空的，则会返回 <code class=" language-php">null</code>：<pre class=" language-php"><code class=" language-php">collect([1, 2, 3, 4])->first(); // 1</code></pre><a name="method-flatmap"></a><h4 id="collection-method"><code class=" language-php">flatMap()</code></h4>对集合内所有子集遍历执行回调，并在最后转为一维集合：<pre class=" language-php"><code class=" language-php">$collection = collect([ ['name' => 'Sally'], ['school' => 'Arkansas'], ['age' => 28] ]); $flattened = $collection->flatMap(function ($values) { return array_map('strtoupper', $values); }); $flattened->all(); // ['name' => 'SALLY', 'school' => 'ARKANSAS', 'age' => '28'];</code></pre><a name="method-flatten"></a><h4 id="collection-method"><code class=" language-php">flatten()</code></h4>将多维集合转为一维集合：<pre class=" language-php"><code class=" language-php">$collection = collect(['name' => 'taylor', 'languages' => ['php', 'javascript']]); $flattened = $collection->flatten(); $flattened->all(); // ['taylor', 'php', 'javascript'];</code></pre>你可以选择性地传入遍历深度的参数：<pre class=" language-php"><code class=" language-php">$collection = collect([ 'Apple' => [ ['name' => 'iPhone 6S', 'brand' => 'Apple'], ], 'Samsung' => [ ['name' => 'Galaxy S7', 'brand' => 'Samsung'] ], ]); $products = $collection->flatten(1); $products->values()->all(); /* [ ['name' => 'iPhone 6S', 'brand' => 'Apple'], ['name' => 'Galaxy S7', 'brand' => 'Samsung'], ] */</code></pre>在这个例子里，调用 <code class=" language-php">flatten</code> 方法时不传入深度参数会遍历嵌套数组降维成一维数组，生成 <code class=" language-php">['iPhone 6S', 'Apple', 'Galaxy S7', 'Samsung']</code>，传入深度参数能让你限制降维嵌套数组的层数。<a name="method-flip"></a><h4 id="collection-method"><code class=" language-php">flip()</code></h4>将集合中的键和对应的数值进行互换：<pre class=" language-php"><code class=" language-php">$collection = collect(['name' => 'taylor', 'framework' => 'laravel']); $flipped = $collection->flip(); $flipped->all(); // ['taylor' => 'name', 'laravel' => 'framework']</code></pre><a name="method-forget"></a><h4 id="collection-method"><code class=" language-php">forget()</code></h4>通过集合的键来移除掉集合中的一个项目：<pre class=" language-php"><code class=" language-php">$collection = collect(['name' => 'taylor', 'framework' => 'laravel']); $collection->forget('name'); $collection->all(); // ['framework' => 'laravel']</code></pre><blockquote class="has-icon note"><div class="flag"><svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:a="http://ns.adobe.com/AdobeSVGViewerExtensions/3.0/" version="1.1" x="0px" y="0px" width="90px" height="90px" viewBox="0 0 90 90" enable-background="new 0 0 90 90" xml:space="preserve"><path fill="#FFFFFF" d="M45 0C20.1 0 0 20.1 0 45s20.1 45 45 45 45-20.1 45-45S69.9 0 45 0zM45 74.5c-3.6 0-6.5-2.9-6.5-6.5s2.9-6.5 6.5-6.5 6.5 2.9 6.5 6.5S48.6 74.5 45 74.5zM52.1 23.9l-2.5 29.6c0 2.5-2.1 4.6-4.6 4.6 -2.5 0-4.6-2.1-4.6-4.6l-2.5-29.6c-0.1-0.4-0.1-0.7-0.1-1.1 0-4 3.2-7.2 7.2-7.2 4 0 7.2 3.2 7.2 7.2C52.2 23.1 52.2 23.5 52.1 23.9z"></path></svg></div> 与大多数其它集合的方法不同，<code class=" language-php">forget</code> 不会返回修改过后的新集合；它会直接修改调用它的集合。</blockquote><a name="method-forpage"></a><h4 id="collection-method"><code class=" language-php">forPage()</code></h4>返回可用来在指定页码上所显示项目的新集合。这个方法第一个参数是页码数，第二个参数是每页显示的个数。<pre class=" language-php"><code class=" language-php">$collection = collect([1, 2, 3, 4, 5, 6, 7, 8, 9]); $chunk = $collection->forPage(2, 3); $chunk->all(); // [4, 5, 6]</code></pre><a name="method-get"></a><h4 id="collection-method"><code class=" language-php">get()</code></h4>返回指定键的项目。如果该键不存在，则返回 <code class=" language-php">null</code>：<pre class=" language-php"><code class=" language-php">$collection = collect(['name' => 'taylor', 'framework' => 'laravel']); $value = $collection->get('name'); // taylor</code></pre>你可以选择性地传入一个默认值作为第二个参数：<pre class=" language-php"><code class=" language-php">$collection = collect(['name' => 'taylor', 'framework' => 'laravel']); $value = $collection->get('foo', 'default-value'); // default-value</code></pre>你甚至可以传入回调函数当默认值。如果指定的键不存在，就会返回回调函数的运行结果：<pre class=" language-php"><code class=" language-php">$collection->get('email', function () { return 'default-value'; }); // default-value</code></pre><a name="method-groupby"></a><h4 id="collection-method"><code class=" language-php">groupBy()</code></h4>根据指定的「键」为集合内的项目分组：<pre class=" language-php"><code class=" language-php">$collection = collect([ ['account_id' => 'account-x10', 'product' => 'Chair'], ['account_id' => 'account-x10', 'product' => 'Bookcase'], ['account_id' => 'account-x11', 'product' => 'Desk'], ]); $grouped = $collection->groupBy('account_id'); $grouped->toArray(); /* [ 'account-x10' => [ ['account_id' => 'account-x10', 'product' => 'Chair'], ['account_id' => 'account-x10', 'product' => 'Bookcase'], ], 'account-x11' => [ ['account_id' => 'account-x11', 'product' => 'Desk'], ], ] */</code></pre>除了传入字符串的「键」之外，你也可以传入回调函数。该函数应该返回你希望用来分组的键的值。<pre class=" language-php"><code class=" language-php">$grouped = $collection->groupBy(function ($item, $key) { return substr($item['account_id'], -3); }); $grouped->toArray(); /* [ 'x10' => [ ['account_id' => 'account-x10', 'product' => 'Chair'], ['account_id' => 'account-x10', 'product' => 'Bookcase'], ], 'x11' => [ ['account_id' => 'account-x11', 'product' => 'Desk'], ], ] */</code></pre><a name="method-has"></a><h4 id="collection-method"><code class=" language-php">has()</code></h4>检查集合中是否含有指定的「键」：<pre class=" language-php"><code class=" language-php">$collection = collect(['account_id' => 1, 'product' => 'Desk']); $collection->has('product'); // true</code></pre><a name="method-implode"></a><h4 id="collection-method"><code class=" language-php">implode()</code></h4><code class=" language-php">implode</code> 方法合并集合中的项目。它的参数依集合中的项目类型而定。假如集合含有数组或对象，你应该传入你希望连接的属性的「键」，以及你希望放在数值之间的拼接字符串：<pre class=" language-php"><code class=" language-php">$collection = collect([ ['account_id' => 1, 'product' => 'Desk'], ['account_id' => 2, 'product' => 'Chair'], ]); $collection->implode('product', ', '); // Desk, Chair</code></pre>假如集合只含有简单的字符串或数字，则只需要传入拼接的字符串作为该方法的唯一参数即可：<pre class=" language-php"><code class=" language-php">collect([1, 2, 3, 4, 5])->implode('-'); // '1-2-3-4-5'</code></pre><a name="method-intersect"></a><h4 id="collection-method"><code class=" language-php">intersect()</code></h4>移除任何指定 <code class=" language-php">数组</code> 或集合内所没有的数值。最终集合保存着原集合的键：<pre class=" language-php"><code class=" language-php">$collection = collect(['Desk', 'Sofa', 'Chair']); $intersect = $collection->intersect(['Desk', 'Chair', 'Bookcase']); $intersect->all(); // [0 => 'Desk', 2 => 'Chair']</code></pre><a name="method-isempty"></a><h4 id="collection-method"><code class=" language-php">isEmpty()</code></h4>如果集合是空的，<code class=" language-php">isEmpty</code> 方法会返回 <code class=" language-php">true</code>：否则返回 <code class=" language-php">false</code>：<pre class=" language-php"><code class=" language-php">collect([])->isEmpty(); // true</code></pre><a name="method-keyby"></a><h4 id="collection-method"><code class=" language-php">keyBy()</code></h4>以指定键的值作为集合项目的键。如果几个数据项有相同的键，那在新集合中只显示最后一项：<pre class=" language-php"><code class=" language-php">$collection = collect([ ['product_id' => 'prod-100', 'name' => 'desk'], ['product_id' => 'prod-200', 'name' => 'chair'], ]); $keyed = $collection->keyBy('product_id'); $keyed->all(); /* [ 'prod-100' => ['product_id' => 'prod-100', 'name' => 'Desk'], 'prod-200' => ['product_id' => 'prod-200', 'name' => 'Chair'], ] */</code></pre>你也可以传入自己的回调函数，该函数应该返回集合的键的值：<pre class=" language-php"><code class=" language-php">$keyed = $collection->keyBy(function ($item) { return strtoupper($item['product_id']); }); $keyed->all(); /* [ 'PROD-100' => ['product_id' => 'prod-100', 'name' => 'Desk'], 'PROD-200' => ['product_id' => 'prod-200', 'name' => 'Chair'], ] */</code></pre><a name="method-keys"></a><h4 id="collection-method"><code class=" language-php">keys()</code></h4>返回该集合所有的键：<pre class=" language-php"><code class=" language-php">$collection = collect([ 'prod-100' => ['product_id' => 'prod-100', 'name' => 'Desk'], 'prod-200' => ['product_id' => 'prod-200', 'name' => 'Chair'], ]); $keys = $collection->keys(); $keys->all(); // ['prod-100', 'prod-200']</code></pre><a name="method-last"></a><h4 id="collection-method"><code class=" language-php">last()</code></h4>返回集合中，最后一个通过指定测试的元素：<pre class=" language-php"><code class=" language-php">collect([1, 2, 3, 4])->last(function ($value, $key) { return $value < 3; }); // 2</code></pre>你也可以不传入参数使用 <code class=" language-php">last</code> 方法以获取集合中最后一个元素。如果集合是空的，则会返回 <code class=" language-php">null</code>：<pre class=" language-php"><code class=" language-php">collect([1, 2, 3, 4])->last(); // 4</code></pre><a name="method-map"></a><h4 id="collection-method"><code class=" language-php">map()</code></h4>遍历整个集合并将每一个数值传入回调函数。回调函数可以任意修改并返回项目，形成修改过的项目组成的新集合：<pre class=" language-php"><code class=" language-php">$collection = collect([1, 2, 3, 4, 5]); $multiplied = $collection->map(function ($item, $key) { return $item * 2; }); $multiplied->all(); // [2, 4, 6, 8, 10]</code></pre><blockquote class="has-icon note"><div class="flag"><svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:a="http://ns.adobe.com/AdobeSVGViewerExtensions/3.0/" version="1.1" x="0px" y="0px" width="90px" height="90px" viewBox="0 0 90 90" enable-background="new 0 0 90 90" xml:space="preserve"><path fill="#FFFFFF" d="M45 0C20.1 0 0 20.1 0 45s20.1 45 45 45 45-20.1 45-45S69.9 0 45 0zM45 74.5c-3.6 0-6.5-2.9-6.5-6.5s2.9-6.5 6.5-6.5 6.5 2.9 6.5 6.5S48.6 74.5 45 74.5zM52.1 23.9l-2.5 29.6c0 2.5-2.1 4.6-4.6 4.6 -2.5 0-4.6-2.1-4.6-4.6l-2.5-29.6c-0.1-0.4-0.1-0.7-0.1-1.1 0-4 3.2-7.2 7.2-7.2 4 0 7.2 3.2 7.2 7.2C52.2 23.1 52.2 23.5 52.1 23.9z"></path></svg></div> 正如集合大多数其它的方法一样，<code class=" language-php">map</code> 返回一个新集合实例；它并没有修改被调用的集合。假如你想改变原始的集合，得使用 <a href="#method-transform"><code class=" language-php">transform</code></a> 方法。</blockquote><a name="method-mapwithkeys"></a><h4 id="collection-method"><code class=" language-php">mapWithKeys()</code></h4>遍历整个集合并将每一个数值传入回调函数。回调函数返回包含一个键值对的关联数组：<pre class=" language-php"><code class=" language-php">$collection = collect([ [ 'name' => 'John', 'department' => 'Sales', 'email' => 'john@example.com' ], [ 'name' => 'Jane', 'department' => 'Marketing', 'email' => 'jane@example.com' ] ]); $keyed = $collection->mapWithKeys(function ($item) { return [$item['email'] => $item['name']]; }); $keyed->all(); /* [ 'john@example.com' => 'John', 'jane@example.com' => 'Jane', ] */</code></pre><a name="method-max"></a><h4 id="collection-method"><code class=" language-php">max()</code></h4>计算指定键的最大值：<pre class=" language-php"><code class=" language-php">$max = collect([['foo' => 10], ['foo' => 20]])->max('foo'); // 20 $max = collect([1, 2, 3, 4, 5])->max(); // 5</code></pre><a name="method-merge"></a><h4 id="collection-method"><code class=" language-php">merge()</code></h4>合并数组进集合。数组「键」对应的数值会覆盖集合「键」对应的数值：<pre class=" language-php"><code class=" language-php">$collection = collect(['product_id' => 1, 'price' => 100]); $merged = $collection->merge(['price' => 200, 'discount' => false]); $merged->all(); // ['product_id' => 1, 'price' => 200, 'discount' => false]</code></pre>如果指定数组的「键」为数字，则「值」将会合并到集合的后面：<pre class=" language-php"><code class=" language-php">$collection = collect(['Desk', 'Chair']); $merged = $collection->merge(['Bookcase', 'Door']); $merged->all(); // ['Desk', 'Chair', 'Bookcase', 'Door']</code></pre><a name="method-min"></a><h4 id="collection-method"><code class=" language-php">min()</code></h4>计算指定「键」的最小值：<pre class=" language-php"><code class=" language-php">$min = collect([['foo' => 10], ['foo' => 20]])->min('foo'); // 10 $min = collect([1, 2, 3, 4, 5])->min(); // 1</code></pre><a name="method-nth"></a><h4 id="collection-method"><code class=" language-php">nth()</code></h4>由每隔第 n 个元素组成一个新的集合：<pre class=" language-php"><code class=" language-php">$collection = collect(['a', 'b', 'c', 'd', 'e', 'f']); $collection->nth(4); // ['a', 'e']</code></pre>你也可以选择传入一个偏移量作为第二个参数<pre class=" language-php"><code class=" language-php">$collection->nth(4, 1); // ['b', 'f']</code></pre><a name="method-only"></a><h4 id="collection-method"><code class=" language-php">only()</code></h4>返回集合中指定键的所有项目：<pre class=" language-php"><code class=" language-php">$collection = collect(['product_id' => 1, 'name' => 'Desk', 'price' => 100, 'discount' => false]); $filtered = $collection->only(['product_id', 'name']); $filtered->all(); // ['product_id' => 1, 'name' => 'Desk']</code></pre>与 <code class=" language-php">only</code> 相反的方法请查看 <a href="#method-only">except</a>。<a name="method-partition"></a><h4 id="collection-method"><code class=" language-php">partition()</code></h4>结合 PHP 中的 <code class=" language-php">list</code> 方法来分开符合指定条件的元素以及那些不符合指定条件的元素：<pre class=" language-php"><code class=" language-php">$collection = collect([1, 2, 3, 4, 5, 6]); list($underThree, $aboveThree) = $collection->partition(function ($i) { return $i < 3; });</code></pre><a name="method-pipe"></a><h4 id="collection-method"><code class=" language-php">pipe()</code></h4>将集合传给回调函数并返回结果：<pre class=" language-php"><code class=" language-php">$collection = collect([1, 2, 3]); $piped = $collection->pipe(function ($collection) { return $collection->sum(); }); // 6</code></pre><a name="method-pluck"></a><h4 id="collection-method"><code class=" language-php">pluck()</code></h4>获取集合中指定「键」所有对应的值：<pre class=" language-php"><code class=" language-php">$collection = collect([ ['product_id' => 'prod-100', 'name' => 'Desk'], ['product_id' => 'prod-200', 'name' => 'Chair'], ]); $plucked = $collection->pluck('name'); $plucked->all(); // ['Desk', 'Chair']</code></pre>你也可以指定最终集合的键：<pre class=" language-php"><code class=" language-php">$plucked = $collection->pluck('name', 'product_id'); $plucked->all(); // ['prod-100' => 'Desk', 'prod-200' => 'Chair']</code></pre><a name="method-pop"></a><h4 id="collection-method"><code class=" language-php">pop()</code></h4>移除并返回集合最后一个项目：<pre class=" language-php"><code class=" language-php">$collection = collect([1, 2, 3, 4, 5]); $collection->pop(); // 5 $collection->all(); // [1, 2, 3, 4]</code></pre><a name="method-prepend"></a><h4 id="collection-method"><code class=" language-php">prepend()</code></h4>在集合前面增加一项数组的值：<pre class=" language-php"><code class=" language-php">$collection = collect([1, 2, 3, 4, 5]); $collection->prepend(0); $collection->all(); // [0, 1, 2, 3, 4, 5]</code></pre>你可以传递第二个参数来设置新增加项的键：<pre class=" language-php"><code class=" language-php">$collection = collect(['one' => 1, 'two' => 2]); $collection->prepend(0, 'zero'); $collection->all(); // ['zero' => 0, 'one' => 1, 'two' => 2]</code></pre><a name="method-pull"></a><h4 id="collection-method"><code class=" language-php">pull()</code></h4>把「键」对应的值从集合中移除并返回：<pre class=" language-php"><code class=" language-php">$collection = collect(['product_id' => 'prod-100', 'name' => 'Desk']); $collection->pull('name'); // 'Desk' $collection->all(); // ['product_id' => 'prod-100']</code></pre><a name="method-push"></a><h4 id="collection-method"><code class=" language-php">push()</code></h4>在集合的后面新添加一个元素：<pre class=" language-php"><code class=" language-php">$collection = collect([1, 2, 3, 4]); $collection->push(5); $collection->all(); // [1, 2, 3, 4, 5]</code></pre><a name="method-put"></a><h4 id="collection-method"><code class=" language-php">put()</code></h4>在集合内设置一个「键/值」：<pre class=" language-php"><code class=" language-php">$collection = collect(['product_id' => 1, 'name' => 'Desk']); $collection->put('price', 100); $collection->all(); // ['product_id' => 1, 'name' => 'Desk', 'price' => 100]</code></pre><a name="method-random"></a><h4 id="collection-method"><code class=" language-php">random()</code></h4><code class=" language-php">random</code> 方法从集合中随机返回一个项目：<pre class=" language-php"><code class=" language-php">$collection = collect([1, 2, 3, 4, 5]); $collection->random(); // 4 - (retrieved randomly)</code></pre>你可以选择性地传入一个整数到 <code class=" language-php">random</code>。如果该整数大于 <code class=" language-php">1</code>，则会返回一个集合：<pre class=" language-php"><code class=" language-php">$random = $collection->random(3); $random->all(); // [2, 4, 5] - (retrieved randomly)</code></pre><a name="method-reduce"></a><h4 id="collection-method"><code class=" language-php">reduce()</code></h4><code class=" language-php">reduce</code> 方法将集合缩减到单个数值，该方法会将每次迭代的结果传入到下一次迭代：<pre class=" language-php"><code class=" language-php">$collection = collect([1, 2, 3]); $total = $collection->reduce(function ($carry, $item) { return $carry + $item; }); // 6</code></pre>第一次迭代时 <code class=" language-php">$carry</code> 的数值为 <code class=" language-php">null</code>；然而你也可以传入第二个参数进 <code class=" language-php">reduce</code> 以指定它的初始值：<pre class=" language-php"><code class=" language-php">$collection->reduce(function ($carry, $item) { return $carry + $item; }, 4); // 10</code></pre><a name="method-reject"></a><h4 id="collection-method"><code class=" language-php">reject()</code></h4><code class=" language-php">reject</code> 方法以指定的回调函数筛选集合。会移除掉那些通过判断测试（即结果返回 <code class=" language-php">true</code>）的项目：<pre class=" language-php"><code class=" language-php">$collection = collect([1, 2, 3, 4]); $filtered = $collection->reject(function ($value, $key) { return $value > 2; }); $filtered->all(); // [1, 2]</code></pre>与 <code class=" language-php">reject</code> 相反的方法可以查看 <a href="#method-filter"><code class=" language-php">filter</code></a> 方法。<a name="method-reverse"></a><h4 id="collection-method"><code class=" language-php">reverse()</code></h4><code class=" language-php">reverse</code> 方法倒转集合内项目的顺序：<pre class=" language-php"><code class=" language-php">$collection = collect([1, 2, 3, 4, 5]); $reversed = $collection->reverse(); $reversed->all(); // [5, 4, 3, 2, 1]</code></pre><a name="method-search"></a><h4 id="collection-method"><code class=" language-php">search()</code></h4><code class=" language-php">search</code> 方法在集合内搜索指定的数值并返回找到的键。假如找不到项目，则返回 <code class=" language-php">false</code>：<pre class=" language-php"><code class=" language-php">$collection = collect([2, 4, 6, 8]); $collection->search(4); // 1</code></pre>搜索是用「宽松」匹配来进行，也就是说如果字符串值是整数那它就跟这个整数是相等的。要使用严格匹配的话，就传入 <code class=" language-php">true</code> 为该方法的第二个参数：<pre class=" language-php"><code class=" language-php">$collection->search('4', true); // false</code></pre>另外，你可以传入你自己的回调函数来搜索第一个通过你判断测试的项目：<pre class=" language-php"><code class=" language-php">$collection->search(function ($item, $key) { return $item > 5; }); // 2</code></pre><a name="method-shift"></a><h4 id="collection-method"><code class=" language-php">shift()</code></h4><code class=" language-php">shift</code> 方法移除并返回集合的第一个项目：<pre class=" language-php"><code class=" language-php">$collection = collect([1, 2, 3, 4, 5]); $collection->shift(); // 1 $collection->all(); // [2, 3, 4, 5]</code></pre><a name="method-shuffle"></a><h4 id="collection-method"><code class=" language-php">shuffle()</code></h4><code class=" language-php">shuffle</code> 方法随机排序集合的项目：<pre class=" language-php"><code class=" language-php">$collection = collect([1, 2, 3, 4, 5]); $shuffled = $collection->shuffle(); $shuffled->all(); // [3, 2, 5, 1, 4] // (generated randomly)</code></pre><a name="method-slice"></a><h4 id="collection-method"><code class=" language-php">slice()</code></h4><code class=" language-php">slice</code> 方法返回集合从指定索引开始的一部分切片：<pre class=" language-php"><code class=" language-php">$collection = collect([1, 2, 3, 4, 5, 6, 7, 8, 9, 10]); $slice = $collection->slice(4); $slice->all(); // [5, 6, 7, 8, 9, 10]</code></pre>如果你想限制返回切片的大小，就传入想要的大小为方法的第二个参数：<pre class=" language-php"><code class=" language-php">$slice = $collection->slice(4, 2); $slice->all(); // [5, 6]</code></pre>返回的切片将会保留原始键作为索引。假如你不希望保留原始的键，你可以使用 <code class=" language-php">values</code> 方法来重新建立索引。<a name="method-sort"></a><h4 id="collection-method"><code class=" language-php">sort()</code></h4>对集合排序。排序后的集合保留着原始数组的键，所以在这个例子里我们用 <a href="#method-values"><code class=" language-php">values</code></a> 方法来把键设置为连续数字的键。<pre class=" language-php"><code class=" language-php">$collection = collect([5, 3, 1, 2, 4]); $sorted = $collection->sort(); $sorted->values()->all(); // [1, 2, 3, 4, 5]</code></pre>假如你需要更高级的排序，你可以传入回调函数以你自己的算法进行<code class=" language-php">排序</code>。参考 PHP 文档的 <a href="http://php.net/manual/en/function.usort.php#refsect1-function.usort-parameters"><code class=" language-php">usort</code></a>，这是集合的 <code class=" language-php">sort</code> 方法在背后所调用的函数。<blockquote class="has-icon tip"><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="56.6px" height="87.5px" viewBox="0 0 56.6 87.5" enable-background="new 0 0 56.6 87.5" xml:space="preserve"><path fill="#FFFFFF" d="M28.7 64.5c-1.4 0-2.5-1.1-2.5-2.5v-5.7 -5V41c0-1.4 1.1-2.5 2.5-2.5s2.5 1.1 2.5 2.5v10.1 5 5.8C31.2 63.4 30.1 64.5 28.7 64.5zM26.4 0.1C11.9 1 0.3 13.1 0 27.7c-0.1 7.9 3 15.2 8.2 20.4 0.5 0.5 0.8 1 1 1.7l3.1 13.1c0.3 1.1 1.3 1.9 2.4 1.9 0.3 0 0.7-0.1 1.1-0.2 1.1-0.5 1.6-1.8 1.4-3l-2-8.4 -0.4-1.8c-0.7-2.9-2-5.7-4-8 -1-1.2-2-2.5-2.7-3.9C5.8 35.3 4.7 30.3 5.4 25 6.7 14.5 15.2 6.3 25.6 5.1c13.9-1.5 25.8 9.4 25.8 23 0 4.1-1.1 7.9-2.9 11.2 -0.8 1.4-1.7 2.7-2.7 3.9 -2 2.3-3.3 5-4 8L41.4 53l-2 8.4c-0.3 1.2 0.3 2.5 1.4 3 0.3 0.2 0.7 0.2 1.1 0.2 1.1 0 2.2-0.8 2.4-1.9l3.1-13.1c0.2-0.6 0.5-1.2 1-1.7 5-5.1 8.2-12.1 8.2-19.8C56.4 12 42.8-1 26.4 0.1zM43.7 69.6c0 0.5-0.1 0.9-0.3 1.3 -0.4 0.8-0.7 1.6-0.9 2.5 -0.7 3-2 8.6-2 8.6 -1.3 3.2-4.4 5.5-7.9 5.5h-4.1H28h-0.5 -3.6c-3.5 0-6.7-2.4-7.9-5.7l-0.1-0.4 -1.8-7.8c-0.4-1.1-0.8-2.1-1.2-3.1 -0.1-0.3-0.2-0.5-0.2-0.9 0.1-1.3 1.3-2.1 2.6-2.1H41C42.4 67.5 43.6 68.2 43.7 69.6zM37.7 72.5H26.9c-4.2 0-7.2 3.9-6.3 7.9 0.6 1.3 1.8 2.1 3.2 2.1h4.1 0.5 0.5 3.6c1.4 0 2.7-0.8 3.2-2.1L37.7 72.5z"></path></svg></div> 要排序嵌套数组或对象的集合，见 <a href="#method-sortby"><code class=" language-php">sortBy</code></a> 和 <a href="#method-sortbydesc"><code class=" language-php">sortByDesc</code></a> 方法。</blockquote><a name="method-sortby"></a><h4 id="collection-method"><code class=" language-php">sortBy()</code></h4>以指定的键排序集合。排序后的集合保留了原始数组键，所以在这个例子中我们用 <a href="#method-values"><code class=" language-php">values</code></a> method 把键设置为连续数字的索引建：<pre class=" language-php"><code class=" language-php">$collection = collect([ ['name' => 'Desk', 'price' => 200], ['name' => 'Chair', 'price' => 100], ['name' => 'Bookcase', 'price' => 150], ]); $sorted = $collection->sortBy('price'); $sorted->values()->all(); /* [ ['name' => 'Chair', 'price' => 100], ['name' => 'Bookcase', 'price' => 150], ['name' => 'Desk', 'price' => 200], ] */</code></pre>你也可以传入自己的回调函数以决定如何排序集合数值：<pre class=" language-php"><code class=" language-php">$collection = collect([ ['name' => 'Desk', 'colors' => ['Black', 'Mahogany']], ['name' => 'Chair', 'colors' => ['Black']], ['name' => 'Bookcase', 'colors' => ['Red', 'Beige', 'Brown']], ]); $sorted = $collection->sortBy(function ($product, $key) { return count($product['colors']); }); $sorted->values()->all(); /* [ ['name' => 'Chair', 'colors' => ['Black']], ['name' => 'Desk', 'colors' => ['Black', 'Mahogany']], ['name' => 'Bookcase', 'colors' => ['Red', 'Beige', 'Brown']], ] */</code></pre><a name="method-sortbydesc"></a><h4 id="collection-method"><code class=" language-php">sortByDesc()</code></h4>与 <a href="#method-sortby"><code class=" language-php">sortBy</code></a> 有着一样的形式，但是会以相反的顺序来排序集合：<a name="method-splice"></a><h4 id="collection-method"><code class=" language-php">splice()</code></h4>返回从指定的索引开始的一小切片项目，原本集合也会被切除：<pre class=" language-php"><code class=" language-php">$collection = collect([1, 2, 3, 4, 5]); $chunk = $collection->splice(2); $chunk->all(); // [3, 4, 5] $collection->all(); // [1, 2]</code></pre>你可以传入第二个参数以限制大小：<pre class=" language-php"><code class=" language-php">$collection = collect([1, 2, 3, 4, 5]); $chunk = $collection->splice(2, 1); $chunk->all(); // [3] $collection->all(); // [1, 2, 4, 5]</code></pre>此外，你可以传入含有新项目的第三个参数以取代集合中被移除的项目：<pre class=" language-php"><code class=" language-php">$collection = collect([1, 2, 3, 4, 5]); $chunk = $collection->splice(2, 1, [10, 11]); $chunk->all(); // [3] $collection->all(); // [1, 2, 10, 11, 4, 5]</code></pre><a name="method-split"></a><h4 id="collection-method"><code class=" language-php">split()</code></h4>将集合按指定组数分解：<pre class=" language-php"><code class=" language-php">$collection = collect([1, 2, 3, 4, 5]); $groups = $collection->split(3); $groups->toArray(); // [[1, 2], [3, 4], [5]]</code></pre><a name="method-sum"></a><h4 id="collection-method"><code class=" language-php">sum()</code></h4>返回集合内所有项目的总和：<pre class=" language-php"><code class=" language-php">collect([1, 2, 3, 4, 5])->sum(); // 15</code></pre>如果集合包含嵌套数组或对象，你应该传入一个「键」来指定要用哪些数值来计算总和：<pre class=" language-php"><code class=" language-php">$collection = collect([ ['name' => 'JavaScript: The Good Parts', 'pages' => 176], ['name' => 'JavaScript: The Definitive Guide', 'pages' => 1096], ]); $collection->sum('pages'); // 1272</code></pre>此外，你可以传入自己的回调函数来决定要用哪些数值来计算总和：<pre class=" language-php"><code class=" language-php">$collection = collect([ ['name' => 'Chair', 'colors' => ['Black']], ['name' => 'Desk', 'colors' => ['Black', 'Mahogany']], ['name' => 'Bookcase', 'colors' => ['Red', 'Beige', 'Brown']], ]); $collection->sum(function ($product) { return count($product['colors']); }); // 6</code></pre><a name="method-take"></a><h4 id="collection-method"><code class=" language-php">take()</code></h4>返回有着指定数量项目的集合：<pre class=" language-php"><code class=" language-php">$collection = collect([0, 1, 2, 3, 4, 5]); $chunk = $collection->take(3); $chunk->all(); // [0, 1, 2]</code></pre>你也可以传入负整数以获取从集合后面来算指定数量的项目：<pre class=" language-php"><code class=" language-php">$collection = collect([0, 1, 2, 3, 4, 5]); $chunk = $collection->take(-2); $chunk->all(); // [4, 5]</code></pre><a name="method-toarray"></a><h4 id="collection-method"><code class=" language-php">toArray()</code></h4>将集合转换成纯 PHP <code class=" language-php">数组</code>。假如集合的数值是 <a href="/docs/5.4/eloquent">Eloquent</a> 模型，也会被转换成数组：<pre class=" language-php"><code class=" language-php">$collection = collect(['name' => 'Desk', 'price' => 200]); $collection->toArray(); /* [ ['name' => 'Desk', 'price' => 200], ] */</code></pre><blockquote class="has-icon note"><div class="flag"><svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:a="http://ns.adobe.com/AdobeSVGViewerExtensions/3.0/" version="1.1" x="0px" y="0px" width="90px" height="90px" viewBox="0 0 90 90" enable-background="new 0 0 90 90" xml:space="preserve"><path fill="#FFFFFF" d="M45 0C20.1 0 0 20.1 0 45s20.1 45 45 45 45-20.1 45-45S69.9 0 45 0zM45 74.5c-3.6 0-6.5-2.9-6.5-6.5s2.9-6.5 6.5-6.5 6.5 2.9 6.5 6.5S48.6 74.5 45 74.5zM52.1 23.9l-2.5 29.6c0 2.5-2.1 4.6-4.6 4.6 -2.5 0-4.6-2.1-4.6-4.6l-2.5-29.6c-0.1-0.4-0.1-0.7-0.1-1.1 0-4 3.2-7.2 7.2-7.2 4 0 7.2 3.2 7.2 7.2C52.2 23.1 52.2 23.5 52.1 23.9z"></path></svg></div> <code class=" language-php">toArray</code> 也会转换所有内嵌的对象为数组。假如你希望获取原本的底层数组，改用 <a href="#method-all"><code class=" language-php">all</code></a> 方法。</blockquote><a name="method-tojson"></a><h4 id="collection-method"><code class=" language-php">toJson()</code></h4>将集合转换成 JSON：<pre class=" language-php"><code class=" language-php">$collection = collect(['name' => 'Desk', 'price' => 200]); $collection->toJson(); // '{"name":"Desk", "price":200}'</code></pre><a name="method-transform"></a><h4 id="collection-method"><code class=" language-php">transform()</code></h4>遍历集合并对集合内每一个项目调用指定的回调函数。集合的项目将会被回调函数返回的数值取代掉：<pre class=" language-php"><code class=" language-php">$collection = collect([1, 2, 3, 4, 5]); $collection->transform(function ($item, $key) { return $item * 2; }); $collection->all(); // [2, 4, 6, 8, 10]</code></pre><blockquote class="has-icon note"><div class="flag"><svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:a="http://ns.adobe.com/AdobeSVGViewerExtensions/3.0/" version="1.1" x="0px" y="0px" width="90px" height="90px" viewBox="0 0 90 90" enable-background="new 0 0 90 90" xml:space="preserve"><path fill="#FFFFFF" d="M45 0C20.1 0 0 20.1 0 45s20.1 45 45 45 45-20.1 45-45S69.9 0 45 0zM45 74.5c-3.6 0-6.5-2.9-6.5-6.5s2.9-6.5 6.5-6.5 6.5 2.9 6.5 6.5S48.6 74.5 45 74.5zM52.1 23.9l-2.5 29.6c0 2.5-2.1 4.6-4.6 4.6 -2.5 0-4.6-2.1-4.6-4.6l-2.5-29.6c-0.1-0.4-0.1-0.7-0.1-1.1 0-4 3.2-7.2 7.2-7.2 4 0 7.2 3.2 7.2 7.2C52.2 23.1 52.2 23.5 52.1 23.9z"></path></svg></div> 与大多数其它集合的方法不同，<code class=" language-php">transform</code> 会修改集合本身。如果你希望创建新集合，就改用 <a href="#method-map"><code class=" language-php">map</code></a> 方法。</blockquote><a name="method-union"></a><h4 id="collection-method"><code class=" language-php">union()</code></h4>将给定的数组合并到集合中，如果数组中含有与集合一样的「键」，集合的键值会被保留：<pre class=" language-php"><code class=" language-php">$collection = collect([1 => ['a'], 2 => ['b']]); $union = $collection->union([3 => ['c'], 1 => ['b']]); $union->all(); // [1 => ['a'], 2 => ['b'], 3 => ['c']]</code></pre><a name="method-unique"></a><h4 id="collection-method"><code class=" language-php">unique()</code></h4><code class=" language-php">unique</code> 方法返回集合中所有唯一的项目。返回的集合保留着原始键，所以在这个例子中我们用 <a href="#method-values"><code class=" language-php">values</code></a> 方法来把键重置为连续数字的键。<pre class=" language-php"><code class=" language-php">$collection = collect([1, 1, 2, 2, 3, 4, 2]); $unique = $collection->unique(); $unique->values()->all(); // [1, 2, 3, 4]</code></pre>当处理嵌套数组或对象的时候，你可以指定用来决定唯一性的键：<pre class=" language-php"><code class=" language-php">$collection = collect([ ['name' => 'iPhone 6', 'brand' => 'Apple', 'type' => 'phone'], ['name' => 'iPhone 5', 'brand' => 'Apple', 'type' => 'phone'], ['name' => 'Apple Watch', 'brand' => 'Apple', 'type' => 'watch'], ['name' => 'Galaxy S6', 'brand' => 'Samsung', 'type' => 'phone'], ['name' => 'Galaxy Gear', 'brand' => 'Samsung', 'type' => 'watch'], ]); $unique = $collection->unique('brand'); $unique->values()->all(); /* [ ['name' => 'iPhone 6', 'brand' => 'Apple', 'type' => 'phone'], ['name' => 'Galaxy S6', 'brand' => 'Samsung', 'type' => 'phone'], ] */</code></pre>你可以传入自己的回调函数来确定项目的唯一性：<pre class=" language-php"><code class=" language-php">$unique = $collection->unique(function ($item) { return $item['brand'].$item['type']; }); $unique->values()->all(); /* [ ['name' => 'iPhone 6', 'brand' => 'Apple', 'type' => 'phone'], ['name' => 'Apple Watch', 'brand' => 'Apple', 'type' => 'watch'], ['name' => 'Galaxy S6', 'brand' => 'Samsung', 'type' => 'phone'], ['name' => 'Galaxy Gear', 'brand' => 'Samsung', 'type' => 'watch'], ] */</code></pre><a name="method-values"></a><h4 id="collection-method"><code class=" language-php">values()</code></h4>返回「键」重新被设为「连续整数」的新集合：<pre class=" language-php"><code class=" language-php">$collection = collect([ 10 => ['product' => 'Desk', 'price' => 200], 11 => ['product' => 'Desk', 'price' => 200] ]); $values = $collection->values(); $values->all(); /* [ 0 => ['product' => 'Desk', 'price' => 200], 1 => ['product' => 'Desk', 'price' => 200], ] */</code></pre><a name="method-when"></a><h4 id="collection-method"><code class=" language-php">when()</code></h4>当第一个参数运算结果为 <code class=" language-php">true</code> 的时候，会执行第二个参数传入的闭包：<pre class=" language-php"><code class=" language-php">$collection = collect([1, 2, 3]); $collection->when(true, function ($collection) { return $collection->push(4); }); $collection->all(); // [1, 2, 3, 4]</code></pre><a name="method-where"></a><h4 id="collection-method"><code class=" language-php">where()</code></h4>以一对指定的「键／数值」筛选集合：<pre class=" language-php"><code class=" language-php">$collection = collect([ ['product' => 'Desk', 'price' => 200], ['product' => 'Chair', 'price' => 100], ['product' => 'Bookcase', 'price' => 150], ['product' => 'Door', 'price' => 100], ]); $filtered = $collection->where('price', 100); $filtered->all(); /* [ ['product' => 'Chair', 'price' => 100], ['product' => 'Door', 'price' => 100], ] */</code></pre>比较数值的时候用了「宽松」匹配方式，查看 <a href="#method-wherestrict"><code class=" language-php">whereStrict</code></a> method来用严格比较的方式过滤。<a name="method-wherestrict"></a><h4 id="collection-method"><code class=" language-php">whereStrict()</code></h4>这个方法与 <a href="#method-where"><code class=" language-php">where</code></a> 方法有着一样的形式；但是会以「严格」匹配来匹配数值：<a name="method-wherein"></a><h4 id="collection-method"><code class=" language-php">whereIn()</code></h4>基于参数中的键值数组进行过滤：<pre class=" language-php"><code class=" language-php">$collection = collect([ ['product' => 'Desk', 'price' => 200], ['product' => 'Chair', 'price' => 100], ['product' => 'Bookcase', 'price' => 150], ['product' => 'Door', 'price' => 100], ]); $filtered = $collection->whereIn('price', [150, 200]); $filtered->all(); /* [ ['product' => 'Bookcase', 'price' => 150], ['product' => 'Desk', 'price' => 200], ] */</code></pre>此方法是用宽松的匹配，你可以使用 <a href="#method-whereinstrict"><code class=" language-php">whereInStrict</code></a> 做比较 <code class=" language-php">严格</code> 的匹配。<a name="method-whereinstrict"></a><h4 id="collection-method"><code class=" language-php">whereInStrict()</code></h4>此方法的使用于 <a href="#method-wherein"><code class=" language-php">whereIn</code></a> 方法类似，只是使用了比较 <code class=" language-php">严格</code> 的过滤。<a name="method-zip"></a><h4 id="collection-method"><code class=" language-php">zip()</code></h4><code class=" language-php">zip</code> 方法将集合与指定数组相同索引的值合并在一起：<pre class=" language-php"><code class=" language-php">$collection = collect(['Chair', 'Desk']); $zipped = $collection->zip([100, 200]); $zipped->all(); // [['Chair', 100], ['Desk', 200]]</code></pre><a name="higher-order-messages"></a><h2><a href="#higher-order-messages">高阶信息传递</a></h2>集合也提供「高阶信息传递支持」，这是对集合执行常见操作的快捷方式。支持高阶信息传递的集合方法有： <code class=" language-php">contains</code>， <code class=" language-php">each</code>， <code class=" language-php">every</code>， <code class=" language-php">filter</code>， <code class=" language-php">first</code>， <code class=" language-php">map</code>， <code class=" language-php">partition</code>， <code class=" language-php">reject</code>， <code class=" language-php">sortBy</code>， <code class=" language-php">sortByDesc</code> 和 <code class=" language-php">sum</code>。每个高阶信息都能作为集合实例的动态属性来访问。例如，我们在集合中使用 <code class=" language-php">each</code> 高阶信息传递方法拉哎对每个对象去调用一个方法：<pre class=" language-php"><code class=" language-php">$users = User::where('votes', '>', 500)->get(); $users->each->markAsVip();</code></pre>同样，我们可以使用 <code class=" language-php">sum</code> 高阶信息传递的方式来统计出集合中用户总共的「投票数」：<pre class=" language-php"><code class=" language-php">$users = User::where('group', 'Development')->get(); return $users->sum->votes;</code></pre></article>