title: Get first n elements from List
body: <p>I have a <code>List</code></p>
  
  <pre><code>val family=List("1","2","11","12","21","22","31","33","41","44","51","55")
  </code></pre>
  
  <p>i want to take its first n elements but the problem is that <code>parents</code> size is not fixed.</p>
  
  <pre><code>val familliar=List("1","2","11") //n=3
  </code></pre>