LINQ grouping and selecting into properties

Question

I'm still trying to get the hang of LINQ and am having trouble with this. I have a List<Data> like so:

GroupId|SectionId|Content
-------------------------
      1|        3|part1-2
      1|        7|part1-1
      3|        3|part3-2
      1|        1|part1-3
      3|        1|part3-3
      3|        7|part3-1

I would like to convert it to IEnumerable<AnonymousType> where each AnonymousType represents one GroupId and each property is linked to a specific SectionId. In other words, you would end up with something like this:

{
  {
    GroupId = 1,
    Part1 = "part1-1", // From SectionId == 7
    Part2 = "part1-2", // From SectionId == 3
    Part3 = "part1-3", // From SectionId == 1
  },
  {
    GroupId = 3,
    Part1 = "part3-1", // From SectionId == 7
    Part2 = "part3-2", // From SectionId == 3
    Part3 = "part3-3", // From SectionId == 1
  }
}

Answer 1

Like this:

 from r in something
 group r by r.GroupId into g
 select new {
      GroupId = g.Key,
      Part1 = g.First(r => r.SectionId == 7).Content,
      Part2 = g.First(r => r.SectionId == 3).Content,
      Part3 = g.First(r => r.SectionId == 1).Content
 }