title: Swift : Sort array by natural order
body: <p>I'm having an dictionary with order here:</p>
  
  <pre><code>var pickerData = [
      "en":"abc",
      "jp":"xyz",
      "fr":"gya",
      "zh-CN":"uio"]
  </code></pre>
  
  <p>But when i println() pickerData.keys.array , the order is not like thit. 
  I want to sort pickerData.keys.array by order above.
  Is it posible?</p>