title: Split and remove duplicate from String
body: <p>I want to split the given string and remove the duplicate from that string. Like I have following string:</p>
  
  <blockquote>
    <p>This is my first post in stack overflow, I am very new in development and I did not have much more idea about the how to post the question.</p>
  </blockquote>
  
  <p>Now I want to split that whole string with white space and that new array will did not have duplicate entry.</p>
  
  <p>How can I do this?</p>