title: Compare two List elements and replace if id is equals
body: <p>I have two lists with Classes </p>
  
  <pre><code>public class Product 
  {
    int id;
    string url;
    ect.
  }
  </code></pre>
  
  <p>I need compare in the old list (10k+ elements) a new list(10 elements) by ID
  and if an id is same just replace data from new List to old list</p>
  
  <p>I think it will be good using LINQ.
  Can you help me how can I use LINQ or there are batter library?</p>