title: what do an undefined method [] mean in rails?
body: <p>I get the following error:</p>
  
  <pre><code>undefined method `[]' for nil:NilClass
  </code></pre>
  
  <p>The related snippet in line 50:</p>
  
  <pre><code> 47: &lt;%=h @contact.date_entered.to_date %&gt;&lt;/br&gt;  
   48: Next event: 
   49: &lt;% next_delayed_todo = @contact.next_delayed_todo %&gt; 
   50: &lt;% unless next_delayed_todo[:event].nil? %&gt;
   52: &lt;%= next_delayed_todo[:event].title %&gt; &lt;/br&gt;
  </code></pre>