title: How to loop through an associative array and get the key?
body: <p>My associative array: </p>
  
  <pre><code>$arr = array(
     1 =&gt; "Value1",
     2 =&gt; "Value2",
     10 =&gt; "Value10"
  );
  </code></pre>
  
  <p>Using the following code, <code>$v</code> is filled with <code>$arr</code>'s values</p>
  
  <pre><code> foreach($arr as $v){
      echo($v);    // Value1, Value2, Value10
   }
  </code></pre>
  
  <p>How do I get <code>$arr</code>'s keys instead?</p>
  
  <pre><code> foreach(.....){
      echo($k);    // 1, 2, 10
   }
  </code></pre>