title: Scala Filter List[Int] Which Exists in other List of Tuples
body: <p>I've a two lists dest (contains:x) and points (x,y)</p>
  
  <pre><code>dest:List[Int] and Points:List[(Int,Int)]
  </code></pre>
  
  <p>I want to filter elements in the dest, if it exists in points <strong>(x==points._1)</strong> i</p>
  
  <pre><code>var newl:List[Int] = List()
  for(x&lt;-dest) if(!points.filter(_._1==x).isEmpty) newl=newl:+x
  </code></pre>
  
  <p>I feel like there must be a better concise way with exists but tuple making it complex. So whats the best way to do the above?</p>