php 如何仅显示 Laravel Blade 模板中集合中的第一项的内容
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How to display something only for the first item from the collection in Laravel Blade template
提问by SoHo
I have a @foreach loop in the Blade template and need to apply special formatting to the first item in the collection. How do I add a conditional to check if this is the first item?
我在 Blade 模板中有一个 @foreach 循环，需要对集合中的第一项应用特殊格式。如何添加条件来检查这是否是第一项？
@foreach($items as $item)
<h4>{{ $item->program_name }}</h4>
@endforeach`
采纳答案by Liam Wiltshire
SoHo,
苏豪，
The quickest way is to compare the current element with the first element in the array:
最快的方法是将当前元素与数组中的第一个元素进行比较：
@foreach($items as $item)
@if ($item == reset($items )) First Item: @endif
<h4>{{ $item->program_name }}</h4>
@endforeach
Or otherwise, if it's not an associative array, you could check the index value as per the answer above - but that wouldn't work if the array is associative.
否则，如果它不是关联数组，您可以根据上面的答案检查索引值 - 但如果数组是关联的，那将不起作用。
回答by Shannon Matthews
Laravel 5.3provides a $loopvariable in foreachloops.
Laravel 5.3$loop在foreach循环中提供了一个变量。
@foreach ($users as $user)
@if ($loop->first)
This is the first iteration.
@endif
@if ($loop->last)
This is the last iteration.
@endif
<p>This is user {{ $user->id }}</p>
@endforeach
回答by Gumma Mocciaro
Just take the key value
只取键值
@foreach($items as $index => $item)
@if($index == 0)
...
@endif
<h4>{{ $item->program_name }}</h4>
@endforeach
回答by Omar Vargas
The major problem with Liam Wiltshire's answer is the performance because:
Liam Wiltshire 回答的主要问题是性能，因为：
reset($items)rewind the pointer of $itemscollection again and again at each loop... always with then same result.
Both $itemand the result of reset($item)are objects, so $item == reset($items)requires a full comparison of its attributes... demanding more processor time.
reset($items)在每个循环中一次又一次地倒回$items集合的指针......总是具有相同的结果。
这两个$项目和结果复位（$项目）都是对象，所以$项目==复位（$项目），需要其属性的全面比较苛刻...更多的处理器时间。
A more efficient and elegant way to do that -as Shannon suggests- is to use the Blade's $loopvariable:
一种更有效、更优雅的方法 -正如香农建议的那样 -是使用 Blade 的$loop变量：
@foreach($items as $item)
@if ($loop->first) First Item: @endif
<h4>{{ $item->program_name }}</h4>
@endforeach
If you want to apply a special format to the first element, then maybe you could do something like (using the ternary conditional operator ?:):
如果您想对第一个元素应用特殊格式，那么也许您可以执行以下操作（使用三元条件运算符?:）：
@foreach($items as $item)
<h4 {!! $loop->first ? 'class="special"': '' !!}>{{ $item->program_name }}</h4>
@endforeach
Note the use of {!!and !!}tags instead of {{}}notation to avoid html encoding of the double quotes around of specialstring.
请注意使用{!!和!!}标记而不是{{}}符号以避免特殊字符串周围双引号的 html 编码。
Regards.
问候。
回答by DBga
To get the first element of a collection in Laravel, you can use :
要在 Laravel 中获取集合的第一个元素，您可以使用：
@foreach($items as $item)
@if($item == $items->first()) {{-- first item --}}
<h4>{{$item->program_name}}</h4>
@else
<h5>{{$item->program_name}}</h5>
@endif
@endforeach
