title: Filter a collection with another list using lambda expression
body: <p>I have 2 lists, the first one is an event list
  the second a list of id countries.</p>
  <p>The event list contains a list of countries, so I am trying to filter the events that contain the countries that are sent in the parameter (list of countries).</p>
  <p>I usually use foreachs for these cases, but I want to know if there is a way to filter these elements using lambda expressions?</p>
  <p>This is my code using foreach</p>
  <pre><code>List&lt;Event&gt; finalList = new List&lt;Event&gt;();
   
   foreach (var eventItem in eventList)
      {
        foreach (var cItem in eventItem.CountrieList)
        {
          foreach (var pItem in countriesListParameter)
           {
             if (cItem .Id == pItem )
               {
                  finalList.Add(eventItem )
               }
  
           }
        }
  
      }
  </code></pre>