title: Check if a string contains a certain character
body: <p>I need to check if my string contain a specific character.  </p>
  
  <p>I tried this:  </p>
  
  <pre><code>charFound :: Char -&gt; String -&gt; Bool
  charFound c s = filter(\x -&gt; x == c) s
  </code></pre>
  
  <p>But it gives me: </p>
  
  <blockquote>
    <p>Couldn't match expected type <code>Bool</code> with actual type <code>[Char]</code>  </p>
  </blockquote>
  
  <p>I know that filter:  </p>
  
  <blockquote>
    <p>returns a list constructed from members of a list (the second argument) fulfilling a condition given by the first argument.  </p>
  </blockquote>
  
  <p>How could I reach the goal and return a bool instead of a list?</p>