循环PHP Url GET [关闭]

Question

I have a little problem and I can't see the solution. It should be very easy. I want to make a liitle script that does a simle thing. When I click:

Class -> go to classes.php?sort=class-desc

Then Class again -> go to classes.php?sort=class-asc

Then Class again -> go to classes.php?sort=class-desc

And so on ...

if (isset($_GET['sort'])) {
        $item = $_GET['sort'];

        $pos = strpos($item, '-');
        $crit = substr($item, 0, $pos);
        $ordine = substr($item, $pos+1);
                echo "<div style='float:left; width: 150px;'><a href=classes.php?sort=class-asc>Class</a></div>";
                echo "<div style='float:left; width: 150px;'><a href=classes.php?sort=avg_grades-asc>General</a></div>";
                echo "<div style='float:left; width: 150px;'><a href=classes.php?sort=abscences-asc>Nr Abscences</a></div>";
                echo "<div style='float:left;width: 180px;'><a href=classes.php?sort=nr_students-asc>Nr Students</a></div><br><br>";


            }else{        

                echo "<div style='float:left; width: 150px;'><a href=classes.php?sort=class-desc>Class</a></div>";
                echo "<div style='float:left; width: 150px;'><a href=classes.php?sort=avg_grades-desc>General</a></div>";
                echo "<div style='float:left; width: 150px;'><a href=classes.php?sort=absente-desc>Nr Abscences</a></div>";
                echo "<div style='float:left;width: 180px;'><a href=classes.php?sort=nr_students-desc>Nr Students</a></div><br><br>";
            $item = 'avg_grades';                
        }

I'm sorry , I know It is an easy thing but I simply don't know where to put the loop.

Thank you

Answer 1

You need another if else statement to check your $ordine variable:

if (isset($_GET['sort'])) {
    $item = $_GET['sort'];

    $sort = explode('-', $item);

    $crit = $sort[0];
    $ordine = $sort[1];

    if ($ordine === 'desc') {
        echo "<div style='float:left; width: 150px;'><a href=classes.php?sort=class-asc>Class</a></div>";
        echo "<div style='float:left; width: 150px;'><a href=classes.php?sort=avg_grades-asc>General</a></div>";
        echo "<div style='float:left; width: 150px;'><a href=classes.php?sort=abscences-asc>Nr Abscences</a></div>";
        echo "<div style='float:left; width: 180px;'><a href=classes.php?sort=nr_students-asc>Nr Students</a></div><br><br>";
    } else {
        echo "<div style='float:left; width: 150px;'><a href=classes.php?sort=class-desc>Class</a></div>";
        echo "<div style='float:left; width: 150px;'><a href=classes.php?sort=avg_grades-desc>General</a></div>";
        echo "<div style='float:left; width: 150px;'><a href=classes.php?sort=absente-desc>Nr Abscences</a></div>";
        echo "<div style='float:left; width: 180px;'><a href=classes.php?sort=nr_students-desc>Nr Students</a></div><br><br>";
        $item = 'avg_grades';
    }
}

Or you could do it a bit shorter by applying the $ordine variable in your a tag href:

if (isset($_GET['sort'])) {
    $item = $_GET['sort'];

    $sort = explode('-', $item);

    $crit = $sort[0];
    $ordine = $sort[1] === 'desc' ? 'asc' : 'desc';

    echo "<div style='float:left; width: 150px;'><a href=classes.php?sort=class-$ordine>Class</a></div>";
    echo "<div style='float:left; width: 150px;'><a href=classes.php?sort=avg_grades-$ordine>General</a></div>";
    echo "<div style='float:left; width: 150px;'><a href=classes.php?sort=absente-$ordine>Nr Abscences</a></div>";
    echo "<div style='float:left; width: 180px;'><a href=classes.php?sort=nr_students-$ordine>Nr Students</a></div><br><br>";
}