title: PHP array_key_exists returning FALSE incorrectly
body: <p>My data is being pulled from a client's CMS, but I'm getting strange results</p>
  
  <pre><code>print_r($appliance_data);
  foreach ($appliance_data as $adKey =&gt; $adValue) {
      print_r($adKey);
      print_r($adValue);
      print_r(array_key_exists($adKey, $appliance_data));
      print_r(isset($appliance_data[$adKey]));
  }
  </code></pre>
  
  <p>With output</p>
  
  <pre><code>Array
  (
      [94] =&gt; stdClass Object
          (
              [operation] =&gt; 0
              [value] =&gt; 0
          )
  
      [102] =&gt; stdClass Object
          (
              [operation] =&gt; 501
              [value] =&gt; 4
          )
  
      [90] =&gt; stdClass Object
          (
              [operation] =&gt; 0
              [value] =&gt; 0
          )
  )
  94
  stdClass Object
  (
      [operation] =&gt; 0
      [value] =&gt; 0
  )
  (boolean) FALSE
  (boolean) FALSE
  102
  stdClass Object
  (
      [operation] =&gt; 501
      [value] =&gt; 4
  )
  (boolean) FALSE
  (boolean) FALSE
  90
  stdClass Object
  (
      [operation] =&gt; 0
      [value] =&gt; 0
  )
  (boolean) FALSE
  (boolean) FALSE
  </code></pre>
  
  <p>Any idea what's causing this?</p>
  
  <p>Edit:  The error is that array_key_exists AND isset <strong>return FALSE for a key obtained by looping over an array!</strong></p>
  
  <pre><code>serialize($appliance_data)
  
  
  
  a:7:{s:2:"94";O:8:"stdClass":3:{s:9:"operation";s:3:"514";s:5:"value";s:1:"2";s:9:"frequency";s:1:"0";}s:3:"102";O:8:"stdClass":3:{s:9:"operation";s:3:"511";s:5:"value";s:1:"4";s:9:"frequency";s:1:"1";}s:2:"90";O:8:"stdClass":3:{s:9:"operation";s:1:"0";s:5:"value";s:1:"0";s:9:"frequency";s:1:"0";}s:2:"68";O:8:"stdClass":3:{s:9:"operation";s:3:"501";s:5:"value";s:1:"3";s:9:"frequency";s:1:"2";}s:2:"66";O:8:"stdClass":3:{s:9:"operation";s:1:"0";s:5:"value";s:1:"0";s:9:"frequency";s:1:"0";}s:2:"84";O:8:"stdClass":3:{s:9:"operation";s:1:"0";s:5:"value";s:1:"0";s:9:"frequency";s:1:"0";}s:2:"98";O:8:"stdClass":3:{s:9:"operation";s:1:"0";s:5:"value";s:1:"0";s:9:"frequency";s:1:"0";}}
  </code></pre>