title: Regular expression to get last 3 characters of a string
body: <p>I want to write a regular expression which will take only last 3 char of a string and append some constant string to it.</p>
  
  <p>I am using C#. I am trying to make regular expression as database entry. Later Read this entry in application and do the transformation based on regex in C#.</p>
  
  <p>Something like : </p>
  
  <pre><code>stringVal.Trim().Substring(0, stringVal.Trim().Length - 3) + ".ConstantValue"
  </code></pre>