title: I wonder which is faster between list.contains() and set.contains() in scala
body: <p>I have a very large collection which contains more than a million <strong>String</strong> elements. It is very often to check whether a coming <strong>String</strong> is in this collection or not. </p>
  
  <p>I wonder which collection is better to use, <strong>List</strong> or <strong>Set</strong>? And why?</p>