wp_session variables being overwritten by $_POST

Question

I am trying to post a form to $wp_session which is working fine - however when I perform it again it overwrites the array that I have put there in the first place, I need the arrays to carry on building up like a collection / shopping basket.

My form:

<form class="form1" method="post" action="" id="form1">
<fieldset>
<ul>
        <label for="name">Exercise ID</label><span>
        <input type="text" name="ExerciseID" placeholder="Exercise ID" class="required" role="input" aria-required="true"/></span>

        <label for="name">Exercise Reps</label><span>
        <input type="text" name="Sets" placeholder="Sets" class="required" role="input" aria-required="true"/></span>

        <label for="name">Exercise Reps</label><span>
        <input type="text" name="Reps" placeholder="Sets" class="required" role="input" aria-required="true"/></span>

        <input  class="submit .transparentButton" value="Next" type="submit" name="Submit"/> 

</ul>
<br/>
</fieldset>
</form>

And the php:

<?php

global $wp_session;

if (isset($_POST['Submit'])) {
 $wp_session['collection'] = array($POST['ExerciseID'],$_POST['Sets'],$POST['Reps']);

}

print_r($wp_session);

?> 

Many thanks in advance.

Answer 1

To have a basket, you have to add the products to an array:

<?php

global $wp_session;

if (isset($_POST['Submit'])) {
 $wp_session['collection'][] = array($_POST['ExerciseID'],$_POST['Sets'],$_POST['Reps']);

}

print_r($wp_session);

?> 

You may want to organize the array by ExerciseID, so you can add to the quantity. I would advice you to create some objects, as they will be more flexible than arrays

Answer 2

Maybe you are looking for this: instead of overwriting you append a new entry to your "session variable" at each run:

<?php

global $wp_session;

if (isset($_POST['Submit'])) {
 $wp_session[]['collection'] = array($_POST['ExerciseID'],$_POST['Sets'],$_POST['Reps']);
}

print_r($wp_session);
?> 

Note the additional [] in the left hand side of the assignment.