title: iterating through a list in haskell
body: <p>I have a list of list of characters <code>::[[Char]]</code>.
  I need to iterate both over the list of strings and also over each character in each string.</p>
  
  <p>Say, my list is present in this variable.</p>
  
  <p><code>let xs</code></p>
  
  <p>Please suggest an easy way to iterate.</p>