title: Split a String on 2nd last occurrence of comma in C#
body: <p>I have a string say</p>
  <pre><code>var str = &quot;xy,yz,zx,ab,bc,cd&quot;;
  </code></pre>
  <p>and I want to split it on the 2nd last occurrence of a comma in C# i.e</p>
  <pre><code>a = &quot;xy,yz,zx,ab&quot;
  b = &quot;bc,cd&quot;
  </code></pre>
  <p>How can I achieve this result?</p>