title: Use LINQ to get items in one List<>, that are in another List<>
body: <p>I would assume there's a simple LINQ query to do this, I'm just not exactly sure how. Please see code snippet below, the comment explains what I'd like to do:</p>
  
  <pre><code>class Program
  {
    static void Main(string[] args)
    {
      List&lt;Person&gt; peopleList1 = new List&lt;Person&gt;();
      peopleList1.Add(new Person() { ID = 1 });
      peopleList1.Add(new Person() { ID = 2 });
      peopleList1.Add(new Person() { ID = 3 });
      peopleList1.Add(new Person() { ID = 4});
      peopleList1.Add(new Person() { ID = 5});
  
      List&lt;Person&gt; peopleList2 = new List&lt;Person&gt;();
      peopleList2.Add(new Person() { ID = 1 });
      peopleList2.Add(new Person() { ID = 4});
  
  
      //I would like to perform a LINQ query to give me only
      //those people in 'peopleList1' that are in 'peopleList2'
      //this example should give me two people (ID = 1&amp; ID = 4)
    }
  }
  
  
    class Person
    {
       public int ID { get; set; }
    }
  </code></pre>