在我的Laravel项目中,我有一个BusController.php文件,我需要运行for()循环。但是,循环不起作用。我也尝试使用刀片进行循环,但也有同样的问题。
BusController.php
<?php
namespace App\Http\Controllers;
use Illuminate\Http\Request;
use DB;
use App\Bus;
use App\Bus_type;
use App\Company;
use App\Http\Requests;
class BusController extends Controller
{
public function index()
{
$buses = Bus::all();
$bus_types = Bus_type::all();
$companies = Company::all();
return view('admin.adding_bus', compact('buses', 'bus_types', 'companies'));
}
public function store(Request $request)
{
$bus = new Bus;
$bus->company_name = $request->company_name;
$bus->bus_type = $request->bus_type;
$bus->bus_number = $request->bus_number;
$bus->no_of_rows = $request->no_of_rows;
$bus->no_of_columns = $request->no_of_columns;
$seats = "";
for ($i = 1; $i <= ($request->no_of_rows * $request->no_of_columns); $i++) {
$seats = $seats . "b";
}
$bus->seats = $seats;
$bus->save();
$buses = Bus::all();
$bus_types = Bus_type::all();
$companies = Company::all();
return view('admin.adding_bus', compact('buses', 'bus_types', 'companies'));
}
}
答案 0 :(得分:3)
确保您已验证从Request
收到的数据。因为如果你没有循环将失败,因为loop condition
将永远是假的。
为了测试它,我在做什么:
$seats = "";
$num_cols = 2;
$num_rows = ''; // assume you don't validate the request, so this can receive empty string too
// $num_rows = 0; // will output the same as above
for($i = 1;$i<=($num_cols * $num_rows);$i++)
{
$seats = $seats."b";
}
var_dump($seats);
输出:
string(0) ""
这里有一个工作:
$seats = "";
$num_cols = 2;
$num_rows = 20; // correctly validated as integer and must be more than 0 because you're doing multiplication here in the following loop
for($i = 1;$i<=($num_cols * $num_rows);$i++)
{
$seats = $seats."b";
}
var_dump($seats);
输出:
string(40) "bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb"