title: Find the missing strings containing int value from a given list
body: <p>Given a list of string, say <code>mystr= ["State0", "State1", "State2", "State5", "State8"]</code>.</p>
  
  <p>I need to find the missing States (here <code>"State3", "State4", "State6", "State7"</code>). Is there a possibility to find it?</p>
  
  <p>Desired output:  <code>mylist = ["State3", "State4", "State6", "State7"]</code></p>