Question

我想检查刀片中是否存在变量..因为我使用了以下行：

@if(is_null($products))
    <div class="alert alert-warning">
        <strong>Sorry!</strong> No Product Found.
    </div>                                      
@else

    @foreach($products as $product)
        //
    @endforeach
@endif

问题是当刀片上有$products我可以在foreach循环内显示但是当我得到空变量时。我无法显示消息No Data Found而不是它只显示空的空间？检查刀片内的变量有什么问题吗？

控制器代码：

public function productSearch(Request $request)
    {
        $name = $request->name; 
        $products = Product::where('name' , 'like', '%'.$name.'%')->get();
        return view('cart.product',compact('products'));
    }

Answer 1

我通常使用PHP count()：

@if(count($products) > 0)
    <div class="alert alert-warning">
        <strong>Sorry!</strong> No Product Found.
    </div>                                      
@else

    @foreach($products as $product)
        //
    @endforeach
@endif

您也可以使用PHP empty()查看：

 @if(!empty($products) > 0)

Answer 2

检查长度怎么样？

@if(count($products)) >= 1)
    @foreach($products as $product)
        //
    @endforeach
@else
    <div class="alert alert-warning">
        <strong>Sorry!</strong> No Product Found.
    </div>                                      
@endif

因为空集（我的意思是具有零元素的数据结构）根本不为空。

php > $a = [];
php > echo is_null($a) ? 1 : 0;
// => 0

Answer 3

对我来说，我会使用这样的逻辑

if(!$products->isEmpty()){
      return view('cart.product', compact('products'));
 }else{
   return view('pageerror', compact('products'));
 }

然后你可以从你的视图文件夹中调用pageerror来显示任何没有数据的页面

Answer 4

@forelse($products as $product)
 <p>do some thing</p>
@empty
 <p>No Products</p>
@endforelse

Refer

Answer 5

您可以查看

@if(isset($products) && !empty($products))
<div class="alert alert-warning">
    <strong>Sorry!</strong> No Product Found.
</div>                                      
@else

    @foreach($products as $product)
    //
    @endforeach
@endif

Answer 6

试试这个

<script src="https://checkout.stripe.com/checkout.js"></script>
            <form id="payment-form" method="post" action="procedures/charge.php" >
                <input id="monthly" type="radio" name="plan-id" value="monthly1" > $10/month<br>
                <input id="annual" type="radio" name="plan-id" value="annual1" > $89/year<br>
                <button type="submit" id="customButton">Sign Up</button>
            </form>
            <script>              

            document.getElementById('customButton').addEventListener('click', function(e) {

             //This is where I'm having my problem

              var plan = document.querySelector('input[name = "plan-id"]:checked').value;
            if(plan = 'monthly1') {
              var description = 'Monthly Subscription';
              var amount = 1000;
            }else if(plan = 'annual1') {
              var description = 'Annual Subscription';
              var amount = 8900;
            }  
              // Open Checkout with further options:
              handler.open({
                name: 'Your Strength Coach',
                description: description,
                amount: amount,
                email: '<?php echo $user['email'] ?>',
              });
              e.preventDefault();
            });
            </script>

Answer 7

is_null查找给定变量是否为NULL。但在我们的情况下，我们需要检查是否为空的值，你可以使用isset（）或empty（）函数在你的情况下是否相同

whileset - 确定变量是否设置且不是NULL和

empty - 确定变量是否为空并且还设置变量

@if(isset($products)  && !empty($products))
        @foreach($products as $product)
        //
    @endforeach                                  
@else

    <div class="alert alert-warning">
        <strong>Sorry!</strong> No Product Found.
    </div>
@endif

Answer 8

正如您在文档中看到的那样：

@forelse ($users as $user)
    <li>{{ $user->name }}</li>
@empty
    <p>No users</p>
@endforelse

此代码允许您解析所有用户并显示它们的列表。如果$users变量为空，则会显示段落

所以对你：

@forelse ($products as $product)
    //
@empty
    <div class="alert alert-warning">
        <strong>Sorry!</strong> No Product Found.
    </div>      
@endforelse

Answer 9

这样做，检查是否有任何记录“-> count（）> 0”，然后执行foreach，其他警报。

@if ($products->count() > 0 )
    @foreach($products as $product)
        //enter code here
    @endforeach
@else
   <div class="alert alert-warning">
        <strong>Sorry!</strong> No Product Found.
    </div>
@endif

Answer 10

从Laravel 5.7开始，您还可以执行以下操作：

friend

Answer 11

我发现完成您在此处尝试的工作最有效（也是迄今为止最简单的方法）。

Assumption #1: You Know The Variable Exists Within The View.

REMEMBER: an empty array will always return false.
Therefore, there is no real need to run it through a function like empty or is null. 
Comparing it to null will tell you if it exists or not.

（您可以通过检查变量是否不等于NULL来绕过此假设（如果您已将该变量传递给视图，则有点肿，所以我认为KEEP IT SIMPLE STUPID [KISS]-如果您愿意，可以在以后进行进一步重构时花点时间。）

无论如何。

我会坚持使用与现在非常相似的代码，也许像这样的代码将成为您视图的代码：

@if(!$products)

    <div class="alert alert-warning">
        <strong>Sorry!</strong> No Product Found.
    </div> 

@else

    @foreach($products as $product)

        // {{ $product . “code goes here.” }}

    @endforeach

@endif

，控制器的代码应如下所示（您几乎已经掌握了，请记住："perfect practice makes perfect!"-但是，是的，控制器代码：

public function productSearch(Request $request)
{
    // Easily obtain the name submitted by the form (I assume via the request object
    // dependency injection magic
    $name = $request->name; 

    // I would consider using the DB builder tool, as follows, as there is more docs on it
    // see: https://laravel.com/docs/5.6/queries - this will return a collection (iterable) 
    $products = DB::table(‘products’)
                ->where('name' , 'like', '%'.$name.’%’)
                ->get();

    // simply passing to the view
    return view('cart.product', compact('products'));
}

您还需要包括产品模型，DB（Laravel）和（通常）请求对象，如下所示：

// Laravel Dependencies 
use Illuminate\Support\Facades\DB;
use Illuminate\Http\Request;
// User Created Model
use App\Product;

希望这对您有所帮助！

如何检查变量是否在laravel刀片中有数据

11 个答案: