Using for() loop to create unique PHP variables

Question

I have an input form that allows me to insert a new quiz into a database. The form looks something like this:

 Question Title
    Question #1
        is_correct_1
        choice#1
        is_correct_2
        choice#2
        is_correct_3
        choice#3
        is_correct_4
        choice#4
    Question #2
    .
    .
    .

Different quizzes will having varying amounts of questions (although each question will always have 4 possibilities). I determine how many questions it will have before the form is constructed. In order to accomplish this I generate the form using a couple for loops. I also initialize the names of different input fields in the same manner. See below:

// Grab number of questions from Admin page
    $num_of_Qs = $_POST['num_of_Qs'];
// Produce form by using for loops
    echo '<form method="post" action="' . $_SERVER['PHP_SELF'] . '">';
    echo '<fieldset><legend>New Quiz Details</legend><label for="title">Quiz Title</label>';
    echo '<input type="text" id="title" name="title" value="" /><br /><br />';
    for ($i = 1; $i <= $num_of_Qs; $i++) {
        echo '<label for="question_'.$i.'">Question #'.$i.'</label>';
        echo '<input type="text" id="question_'.$i.'" name="question_'.$i.'" value="" /><br /><br />';
        for ($x = 1; $x <= 4; $x++) {
            echo '<label for="is_correct_'.$i.'_'.$x.'">is_correct_'.$x.'</label>';
            echo '<input type="text" id="is_correct_'.$i.'_'.$x.'" name="is_correct_'.$i.'_'.$x.'" value="" /><br />';
            echo '<label for="choice_'.$i.'_'.$x.'">Choice #'.$x.'</label>';
            echo '<input type="text" id="choice_'.$i.'_'.$x.'" name="choice_'.$i.'_'.$x.'" value="" /><br /><br />';
        }
    }
    echo '</fieldset><input type="hidden" name="num_of_Qs" value="'.$num_of_Qs.'" />';
    echo '<input type="submit" value="Create" name="create" /></form>';

So, the variables end up looking something like this:

$title
$question_1
is_correct_1_1
choice_1_1  // first question, first choice
is_correct_1_2
choice_1_2 // first question, second choice
...

When I go to store those variables by grabbing it using the $_POST function, I'm having trouble. Here is my code:

// If user has submitted New Quiz data
    if (isset($_POST['create'])) {
        $num_of_Qs = $_POST['num_of_Qs'];
        $title = $_POST['title'];
        for ($i = 1; $i <= $num_of_Qs; $i++) { 
            $question_$i = $_POST['question_'.$i.''];
            for ($x = 1; $x <= 4; $x++) {
                $is_correct_$i_$x = $_POST['is_correct_'.$i.'_'.$x''];
                $choice_$i_$x = $_POST['choice_'.$i.'_'.$x.''];
            }
        }
        print_r($title);
        print_r($question_1);

        exit();
    }

I'm wondering if there is a way to grab the values from the form based on the structure I have determined for my variable names. The specific problem lies in $question_$i = .... Can I salvage this code or do I need to rethink the way I am naming these variables? Thanks!

helloandre · Accepted Answer · 2011-10-15 20:16:26Z

5

To answer your question, you can reference variables with strings like

$var_1 = "hello";
echo ${"var_1"};
// or
$str = "var_1";
echo $$str;

BUT DON'T DO THAT

You want to store these values in an array.

$question[$i] = $_POST['...'];
$is_correct[$i][$x] = $_POST['...'];

edited Oct 15, 2011 at 20:16

answered Oct 15, 2011 at 2:57

helloandre

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1 Comment

Michael Mior Over a year ago

+1 for the caution against creating large numbers of unnecessary variables.

Azmisov · Accepted Answer · 2011-10-15 02:58:25Z

0

Why don't you name your inputs as arrays?

<input type='text' name='correct[]'/>

Then whey you send the form with POST, the $_POST['correct'] will be an array.

answered Oct 15, 2011 at 2:58

Azmisov

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