How do I iterate an IGrouping Interface?

Question

Ive got ths really annoying issue I have grouped a set of data and I cant get to the data within the group. I can get to the key bit not the data..

I have a load of

Answer 1

Though maybe obvious for others one can also use:

var groups = Data.GroupBy(x => x.Period);

foreach(var group in groups)
{
   List dataListByPeriod = group.ToList();
   //use this list
}