title: how to do substring in reverse mode in c#
body: <p>My string is "csm15+abc-indiaurban@v2". I want only "indiaurban" from my string. what I am doing right now is :</p>
  
  <pre><code>var lastindexofplusminus = input.LastIndexOfAny(new char[]{'+','-'});
  
  var lastindexofattherate = input.LastIndexOf('@');
  
  string sub = input.Substring(lastindexofplusminus,lastindexofattherate);
  </code></pre>
  
  <p>but getting error "Index and length must refer to a location within the string."</p>
  
  <p>Thanks in Advance.</p>