title: Concatenate Swift Array of Int to create a new Int
body: <p>How can you make an <code>Array&lt;Int&gt;</code> (<code>[1,2,3,4]</code>) into a regular <code>Int</code> (<code>1234</code>)? I can get it to go the other way (splitting up an <code>Int</code> into individual digits), but I can't figure out how to combine the array so that the numbers make up the digits of a new number.</p>