title: understanding line of ruby code
body: <p>I am studying the source code for fat free CRM.  I am trying to understand what this specific line of code in one of the app helpers does:</p>
  
  <pre><code>options[:selected] = (@account &amp;&amp; @account.id) || 0
  </code></pre>
  
  <p>It seems to be setting the value of the options hash with key <code>:selected</code> to the value of the instance variable <code>@account</code> or <code>0</code> (if <code>@account</code> doesn't exist).</p>
  
  <p>What is the <code>&amp;&amp; @account.id</code> doing? </p>