PHP 500（内部服务器错误） - 遇到非数字值？

Question

I want to have a autocomplete search input with jQuery and Laravel. But I'm getting an error when the user write at least 2 letters in the search input:

GET http://proj.test/autocomplete-search?term=ca 500 (Internal Server Error)

Do you know where is the issue? I want to show the conferences based on the letters inserted by the user in the search form.

The search input:

<div class="col col-md-6">
    <h4 class="text-white  text-center font-weight-bold">Search</h4>
    <form class="main-search">
        <input type="text" id="search" class="autocomplete dropdown-toggle" placeholder="Conference, Citiy, Category">
    </form>
</div>

Laravel routes:

Route::get('/autocomplete-search', 'AutocompleteController@search');

Laravel AutomcompleteController:

class AutocompleteController extends Controller
{
    public function search(Request $request){
        $search = $request->term;
        $conferences = Conference::where('name', 'LIKE', '%'.$search.'%')->get();

        $data= [];
        foreach ($conferences as $key => $value){
            $data[] = ['id'=>$value->id, 'value' => $value->id + " " + $value->name];
        }

        //dd($data);
        return response($data);
    }
}

jquery:

$("#search").autocomplete({
   source: "{{ URL::to('autocomplete-search') }}",
   minLength: 2,
   select:function(key, value)
   {
       console.log(value);
   }
});

EDIT: In the Network tab the error shows as:

{message: "A non-numeric value encountered", exception: "ErrorException",…}

and points to this line:

{function: "search", class: "App\Http\Controllers\AutocompleteController", type: "->"}". In "$data[] = ['id'=>$value->id, 'value' => $value->id + " " + $value->name];

Answer 1

You've used the addition operator (+) when you need to use the string concatenation operator (.).

So

$data[] = ['id'=>$value->id, ' value' => $value->id + " " + $value->name]

needs to become

$data[] = ['id'=> $value->id, 'value' => $value->id . " " . $value->name]

otherwise PHP thinks you're trying to do addition on these fields, when in fact they're text which you want to place into a single variable.

See http://php.net/manual/en/language.operators.php for info about which operators do what in PHP.