title: PHP test for empty and/or null and/or unset array
body: <p>I want to keep this short. I don't know if I have the terminology correct, but I got this example from the <em>Codeigniter handbook Vol.1</em>. </p>
  
  <pre><code>if (count($args) &gt; 1 || is_array($args[0]))
  </code></pre>
  
  <p>I've run into this problem numerous times. Depending on the datatype different tests are more appropriate. Some tests will just fail in unexpected ways.</p>
  
  <p>How does one determine the most appropriate, and possibly, the most concise test?</p>
  
  <p>Just to be clear I'm looking for the most effective way to test if an object/variable is ready to use, regardless of the datatype, if that's possible.</p>
  
  <p>Also I don't want the solution to apply merely to lists like in the example. It should be widely applicable.</p>