更新后Xampp中的致命错误：无法使用isset（）

Question

When I open old project in Xampp I have trouble with isset code. Actually its happening since I updated my Xampp from 1.7.3 to 3.2.1 xampp. Looks like the error is in this line:

for ($i = 1; $i <= CITY_COUNT; $i++) {
    for ($j = 1; $j <= CITY_COUNT; $j++) {
        if (isset(@$_POST[$i . '_' . $j]))
            //
            $distances[$i][$j] = @$_POST[$i . '_' . $j];
        else if (isset(@$_POST[$j . '_' . $i]))
            $distances[$i][$j] = @$_POST[$j . '_' . $i];
        else
            $distances[$i][$j] = 32767;
    }
}

I am getting an fatal error. The error say " Fatal error: Cannot use isset() on the result of an expression (you can use "null !== expression" instead) " But I don't know what's wrong in that code.. in old xampp 1.7.3 I didn't saw that error.

Please guide me.

Answer 1

Just remove isset where you are using $_POST. This will automatically check if the value is there else you have settled default value.

Updated

As per @magnus idea, remove @ before $_POST.

for ($i = 1; $i <= CITY_COUNT; $i++) {
    for ($j = 1; $j <= CITY_COUNT; $j++) {
        if ($_POST[$i . '_' . $j] != '')
            //
            $distances[$i][$j] = $_POST[$i . '_' . $j];
        else if ($_POST[$j . '_' . $i] != '')
            $distances[$i][$j] = $_POST[$j . '_' . $i];
        else
            $distances[$i][$j] = 32767;
    }
}