title: foreach, unexpected result for element, which key is 0
body: <p>I have this code</p>
  
  <pre><code>$arr = array(
      "0"=&gt;"http://site.com/somepage/param1/param2/0",
      "1"=&gt;"http://site.com/somepage/param1/param2/1",
      "thispage" =&gt; "http://site.com/somepage/param1/param2/2",
      "3"=&gt; "http://site.com/somepage/param1/param2/3"
  );
  
  
  
  foreach ($arr as $k=&gt;$v) {
      if ($k == "thispage") {
          echo $k." ";
      }
      else {
          echo '&lt;a href="'.$v.'"&gt;'.$k.'&lt;/a&gt; ';
      }
  }
  </code></pre>
  
  <p>Its surprise, for first element <code>"0"=&gt;"http://site.com/somepage/param1/param2/0",</code> not created link, (for other elements works fine)</p>
  
  <p>If replace first element key <code>0</code> on something other, for example <code>4</code>, now links created. What is wrong ?</p>