title: Test if one array is a subset of another
body: <p>How can I determine if one array is a subset of another (all elements in the first are present in the second)?</p>
  
  <pre><code> $s1 = "string1&gt;string2&gt;string3&gt;string4&gt;string5&gt;string6&gt;";
   $arr1 = explode("&gt;", $s1);
   $s2 = "string1&gt;string4&gt;string5";
   $arr2 = explode("&gt;", $s2);
  
   $isSubset = /* ??? */
  </code></pre>