title: Retrieve key value of multidimensional array in PHP
body: <p>How do I reference the key of a multidimensional array?  Here is the array:</p>
  
  <pre><code>Array
  (
  [Nov 18, 2011] =&gt; Array
      (
          [C] =&gt; 3
          [I] =&gt; 1
      )
  [Nov 22, 2011] =&gt; Array
      (
          [C] =&gt; 2
      )
  )
  </code></pre>
  
  <p>and here is the foreach loop:  </p>
  
  <pre><code>foreach($array as $date) { 
      foreach ($date as $k=&gt;$v) {         
          // how to I reference the value of $billdate here ?
      }            
  } 
  </code></pre>
  
  <p>It is easy enough to reference the <code>$k</code> and <code>$v</code> inside the <strong>inner</strong> <code>foreach</code> loop, but how do I reference the date value contained in the <strong>outer</strong> <code>foreach</code> loop?</p>
  
  <p>Thank you for your help.</p>