Swift optionals and if let statement
<p>I am comparing the following code snippets:</p>

<pre><code>var num = Int(numTextField.text!)!
</code></pre>

<p>to</p>

<pre><code>if let num = Int(numTextField.text!) {}
</code></pre>

<p>Can someone explain to me how the if left statement doesn't need the second "!".
Does assignment in an if let block implicitly unwrap the Int optional? If it does can anyone explain the mechanisms at work?</p>

<p>Thanks in advance!</p>