title: How to fix 'characters' is unavailable: Please use String directly in swift 5
body: <p>i've some code to filtering number inside variable.</p>
  
  <p>Here's the code:</p>
  
  <pre><code>var numbers = String(anotherNumbers.characters.filter { "01234567890.".characters.contains($0) })
  </code></pre>
  
  <p>In the swift 3, this code working correctly. But in the Swift 5, i get an error <code>'characters' is unavailable: Please use String directly</code></p>
  
  <p>How to fix this error?
  Thankyou.</p>