title: Ruby, !! operator (a/k/a the double-bang)
body: <blockquote>
    <p><strong>Possible Duplicate:</strong><br>
    <a href="https://stackoverflow.com/questions/524658/what-does-mean-in-ruby">What does !! mean in ruby?</a>  </p>
  </blockquote>
  
  
  
  <p>Hi,</p>
  
  <p>I'm new to Ruby and can't find anywhere description of what "!!" means. </p>
  
  <p>Here's an example:</p>
  
  <pre><code>def signed_in?
    !!current_user
  end
  </code></pre>
  
  <p>If this is a double negative, why not to say:</p>
  
  <pre><code>def signed_in?
    current_user
  end
  </code></pre>
  
  <p>Please help.</p>