foreach 限制循环中断 blade laravel

Question

我的Table：'blog'

  id  |   cat  |  title
---------------------------
   1  |   3,4  |  Post 01    X
   2  |   1,2  |  Post 02
   3  |   4,2  |  Post 03    X
   4  |   3,2  |  Post 04
   5  |   1,1  |  Post 05
   6  |   3,1  |  Post 06
   7  |   3,2  |  Post 07
   8  |   3,4  |  Post 08    X
   9  |   1,4  |  Post 09    X
  10  |   2,4  |  Post 10    X
  11  |   4,6  |  Post 11    X
  12  |   4,7  |  Post 12    X
  13  |   4,1  |  Post 13    X
  14  |   7,4  |  Post 14    X
  15  |   4,2  |  Post 15    X

我的路线：routes/web.php

<?php
use Illuminate\Support\Facades\Route;
use App\Http\Controllers\Frontend\CategoryController

Route::get('/cat',[CategoryController::class,'CAT']);

我的控制器：app/Http/Controllers/Frontend/CategoryController.php

<?php 
namespace App\Http\Controllers\Frontend;
use App\Http\Controllers\Controller;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\DB;
use Illuminate\Support\Facades\Route;
class CategoryController extends Controller
{
    public function CAT(){
        $cats = DB::table('blog')->orderBy('id','DESC')->get();
        $cat_select = '4';
        $data = array( 'cats' => $cats, 'cat_select' => $cat_select, );
        return view('frontend.category', $data );
    }
}

我的 Blade: resources/views/frontend/category.blade.php

@foreach($cats->take(5) as $row)
    @php
        $data = $row->cat;
        $sep_cat = explode(',' , $data);
    @endphp
    @foreach ($sep_cat as $cat)
         @if ( $cat == $cat_select )
            {{$row->id}} |  {{$row->title}}
        @endif
    @endforeach 
@endforeach

输出：

1  |  Post 01
3  |  Post 03

但我想显示输出如下：( $cat_select = '4' and Limit: 5 )

1  |  Post 01
3  |  Post 03
8  |  Post 08
9  |  Post 09
10 |  Post 10

我检查了下面这个 link 但它没有正确显示：

如何更改代码？

Answer 1

您的 $cats->take(5) 获取前 5 个结果（因此 id 1 到 5. 8、9 然后不属于该选择的一部分）。您可以使用每个 post 更新的计数器，然后在 5:

之后中断

@php $i = 0; @endphp
@foreach($cats as $row)
    @if (in_array($cat_select, explode(',' , $row->cat)))
        {{$row->id}} |  {{$row->title}}
        @php $i++; @endphp
        @if($i == 5) @break @endif
    @endif
@endforeach

（我也稍微清理了你的 blade）

Answer 2

最佳做法是先根据您的条件设置查询。做你的 app/Http/Controllers/Frontend/CategoryController.php:

<?php 
namespace App\Http\Controllers\Frontend;
use App\Http\Controllers\Controller;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\DB;
use Illuminate\Support\Facades\Route;
class CategoryController extends Controller
{
    public function CAT(){
        $cat_select = '4';
        $cats = DB::table('blog')->where('cat', 'like', "$cat_select,%")
                 ->orWhere('cat', 'like', "%,$cat_select")
                 ->orWhere('cat', 'like', "%,$cat_select,%")
                 ->orderBy('id','DESC')->get();
        
        $data = array( 'cats' => $cats, 'cat_select' => $cat_select, );
        return view('frontend.category', $data );
    }
}

但我建议您在 table:

中使用 json

  id  |   cat  |  title
---------------------------
   1  |   [3,4]  |  Post 01    X
   2  |   [1,2]  |  Post 02
   3  |   [4,2]  |  Post 03    X

因此您的查询将更改为：

        $cats = DB::table('blog')->whereJsonContains('cat', $cat_select)
                 ->orderBy('id','DESC')->get();

和 resources/views/frontend/category.blade.php 将是：

@foreach($cats as $row)
    {{$row->id}} |  {{$row->title}}
@endforeach

Answer 3

而不是 foreach loop 使用 laravel 查询获取 5 条记录 cat_select = 4 使用 whereRaw 查询

$cats = DB::table('blog')->whereRaw("find_in_set('4',cat)")->limit(5)->get();

@foreach($cats as $row)
    {{$row->id}} |  {{$row->title}}    
@endforeach

所以减少代码并获得更快的输出。

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laravel-blade