Adding Across Arrays
<p>I structured the item information in an unorthodox way, it is stored in three different arrays and are related by the key. I am looking to Sum the Quantities by ItemID. </p>

<pre><code>   1. Array #1 ItemID
        $_SESSION["item_id"][] 
             1 =&gt; 1, 2 =&gt; 1, 3 =&gt;2
   2. Array #2 Size 
        $_SESSION["size"][]   
             1 =&gt; S, 2 =&gt; L, 3 =&gt;S
   3. Array #3 Quantity 
        $_SESSION["count"][]
             1 =&gt; 250, 2 =&gt;750, 3=&gt;250
</code></pre>

<p>The result should be as follows:</p>

<p>ItemID # 1 --> Quantity 1000</p>

<p>ItemID # 2 --> Quantity 250</p>

<p>Could someone could help me with a function ?</p>
