title: How does one compare a string to the next string in a list?
body: <p>I'm writing a small NLP algorithm and I need to do the following: </p>
  
  <p>For every string x in the list <code>["this", "this", "and", "that"]</code>, if the string <code>x</code> and the next string are identical, I want to print the string. </p>