title: Add elements in a list in Prolog
body: <p>I want to extract elements from a list and add them into another new list.How can I do this-</p>
  
  <pre><code>L=[['abc',18],['bcd',19],['def',20]],
  nth1(Count,L,List1),
  nth1(2,List1,Value),
  **NOW I WANT TO PUT THIS Valie in another new list.So finally new list will have 
     New=[18,19,20]**
  </code></pre>
  
  <p>How can I keep adding elements in a new list??</p>