title: All combinations of r elements from given array php
body: <p>Given an array such as the following</p>
  
  <pre><code>$array = ('1', '2', '3', '4', '5', '6', '7');
  </code></pre>
  
  <p>I'm looking for a method to generate all possible combinations, with a minimum number of elements required in each combination r. (eg if r = 5 then it will return all possible combinations containing at least 5 elements)</p>