title: Haskell: Removing duplicates tuples from a list?
body: <p>I'm trying to get from the before to after state. Is there a convenient Haskell function for removing duplicate tuples from a list? Or perhaps it is something a bit more complicated such as iterating through the entire list?</p>
  
  <pre><code>Before: the list of tuples, sorted by word, as in
     [(2,"a"), (1,"a"), (1,"b"), (1,"b"), (1,"c"), (2,"dd")]
  After: the list of sorted tuples with exact duplicates removed, as in
     [(2,"a"), (1,"a"), (1,"b"), (1,"c"), (2,"dd")]
  </code></pre>