使用post数据的数组搜索获取数组中的下一个元素

Question

Each time I click the next button it's stuck up in the 1st element that has been search in the array. Here's my sample code:

<?php

$letter = 'A';

if (isset($_POST["next"])) 
{
    if(isset($next))
    {
        unset($letter);
        $letter = $next;
    }

    $alphabet = array('A', 'B', 'C', 'D', 'E');

    $get = array_search($letter, $alphabet);

    $next = $alphabet[$get + 1];

    echo $next;
}

?>

<form name="alphabet" method="post"> 
<input type="submit"  name="next" value="next"/>
</form>

The output is:

B

My desired output is:

A-> B-> C-> D

how to go to every next element everytime I click the next button & if the last element shown I want it to go to the 1st element in the array like it was loop to the 1st element. I don't want to use a $_GET I want a $_POST. Kindly help me out this one? Thank you.

Answer 1

Try this. You need to post the variable back to the script so that upon each page load, it can know what the previous value was.

<?php
        $letter = 'A';

        if (isset($_POST["letter"]))
        {
            $letter = $_POST["letter"];

            $alphabet = array('A', 'B', 'C', 'D', 'E');

            $get = array_search($letter, $alphabet);

            if($get < (count($alphabet) - 1))
            {
                $get++;
            }
            else
            {
                $get = 0;
            }

            $letter = $alphabet[$get];

            echo $letter;
        }

        ?>

        <form name="alphabet" method="post">
            <input type="hidden"  name="letter" value="<?php echo $letter ?>" />
            <input type="submit"  value="next" />
        </form>

Edit : Have added a check on the index variable $get to only increment if it is not at the end of the array, otherwise it should reset.

Answer 2

Try this. We are passing the current letter as a hidden post variable.

<?php

$alphabet = array('A', 'B', 'C', 'D', 'E');
$next = 'A';   //for the first call of page.
if (isset($_POST["next"])) 
{

    $letter = $_POST['letter'];

    $get = array_search($letter, $alphabet);

    $next = $alphabet[($get + 1)%count($alphabet)];  //for loop over array

}

echo $next;
?>

<form name="alphabet" method="post"> 
<input type="hidden"  name="letter" value="<?php echo $next;?>"/>
<input type="submit"  name="next" value="next"/>
</form>