title: contains & indexOf not working with alphanumeric string
body: <p>I am trying to get a string between two strings but <code>contains</code> &amp; <code>indexOf</code> method not working. </p>
  
  <p>Please help me out if someone had the same issue.</p>
  
  <p>Main String = [)>061PKDU 127 161/3R4C22PDUW 30 016D20110714STU8X195955</p>
  
  <p>I am trying to find string <strong>16D</strong> but <code>contains</code> method giving me false &amp; <code>indexOf</code> always returning -1</p>
  
  <p>Please let me know if am doing anything wrong otherwise your help would be appreciated. Thanks!</p>
  
  <p>Please have a look at the screenshot for more info, </p>
  
  <p><a href="https://i.stack.imgur.com/8Ns1C.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/8Ns1C.png" alt="enter image description here"></a></p>