quick php syntax question
<pre><code>$items = (isset($_POST['items'])) ? $_POST['items'] : array();
</code></pre>

<p>I don't understand the last snippet of this code "? $_POST['items'] : array();"</p>

<p>What does that combination of code do exactly?</p>

<p>I use it to take in a bunch of values from html text boxes and store it into a session array. But the problem is, if I attempt to resubmit the data in text boxes the new array session  overwrites the old session array completely blank spaces and all.</p>

<p>I only want to overwrite places in the array that already have values. If the user decides to fill out only a few text boxes  I don't want the previous session array data to be overwritten by blank spaces (from the blank text boxes).</p>

<p>I'm thinking the above code is the problem, but I'm not sure how it works. Enlighten me please. </p>
