title: Haskell List of Tuple Search
body: <p>I have a list of tuples like this:</p>
  
  <pre><code>[("username", 123), ("df", 54), ("as",2 34)]
  </code></pre>
  
  <p>I need to search the value based on username. I have using lookup but i need to change the value of the integer and write back to file. My logic of this is to delete the tuple and insert another new tuple value rather than change it. </p>
  
  <p>Any idea how to do this ?</p>