title: Need example of updating set data in Linq
body: <p>I have two sets of data where I need to update one set from another.  I have a large set of data so need to find an efficient way to do this.  </p>
  
  <pre><code>public class Data
  {
      int id {get; set;}
      string comment {get; set;}
  }
  public class DataComments
  {
      int id {get; set;}
      string comment {get; set;}
  }
  </code></pre>
  
  <p>I have 2 collections, one of Data and another of DataComments.  e.g. List.  I need to update class "Data" with comments found in the List collection if it exists.  When complete I need all rows in Data and have it's comment property updated if there's a intersection in DataComments.  Bottom line I just need to update one set of data from another if there's anything found.  I thought the intersection might be a way to do this.</p>