title: Why do I get the error "Argument type 'String' does not conform to expected type 'sequence'
body: <p>I'm trying to convert user input from a textField to an array.
  I followed the code that was offered here <a href="https://stackoverflow.com/a/27501398">https://stackoverflow.com/a/27501398</a></p>
  
  <pre><code>let someString : String = someTextField.text!
  let someArray = Array(someString).map { String($0).toInt()! }
  </code></pre>
  
  <p>But then I get this error:</p>
  
  <pre><code> Argument type "String" does not conform to expected type "Sequence"
  </code></pre>
  
  <p>What am I doing wrong?</p>