title: array .any? or .empty? conundrum in Rails
body: <p>I'm attempting to check if there is anything at all in an array, and I'm confused about the results.</p>
  
  <pre><code>markets.any? do |m|
      m["market"]["name"] == "Atlanta"
  end.should be_true
  </code></pre>
  
  <p>Returns <code>You have a nil object when you didn't expect it!, You might have expected an instance of Array.</code></p>
  
  <p>But</p>
  
  <pre><code>markets.empty? do |m|
      m["market"]["name"] == "Atlanta"
  end.should be_false
  </code></pre>
  
  <p>Doesn't error. But it seems backwards to me, because I want to test for true, not false. And I don't get why .any? thinks it's nill. BTW, there are 3 items in the array, and none are nil.</p>