title: I want to group list of list
body: <p>The structure of class along with sample data here.</p>
  
  <pre><code>class Student
  {
      public Int32 Id { get; set; } 
  
      public string Name { get; set; }
  
      public Int32 Age { get; set; }
  
      public List&lt;string&gt; subjects { get; set; }
  
  }
  
  class Program
  {
      static void Main( string[] )
      {
          List&lt;Student&gt; students = new List&lt;Student&gt;()
          {
             new Student(){ Id=1 ,Name="Pratik", Age=24, subjects=new List&lt;string&gt;(){"s1", "s2"}},
             new Student(){ Id=2, Name="Ashish", Age=28, subjects=new List&lt;string&gt;{"s1", "s4"}},
             new Student(){ Id=3, Name="Umesh", Age=24, subjects=new List&lt;string&gt;(){"s1" }},
             new Student(){ Id=4, Name="Ajay", Age=28, subjects=new List&lt;string&gt;(){"s5", "s1"}},
             new Student(){ Id=5, Name="Vijay", Age=24, subjects=new List&lt;string&gt;(){"s1"}},
             new Student(){ Id=6, Name="Shital", Age=24, subjects=new List&lt;string&gt;(){"s2", "s3"}}
          };
  
          ...
      } 
  </code></pre>
  
  <p>I want to group <code>subjects</code> on <code>Names</code> for ex. </p>
  
  <pre><code>s2 Pratik, Shital 
  </code></pre>