Since IGrouping<TKey, TElement>
implements IEnumerable<TElement>
, you can use SelectMany
to put all the IEnumerables
back into one IEnumerable
all together:
List<smth> list = new List<smth>();
IEnumerable<IGrouping<int, smth>> groups = list.GroupBy(x => x.id);
IEnumerable<smth> smths = groups.SelectMany(group => group);
List<smth> newList = smths.ToList();
Here’s an example that builds/runs: https://dotnetfiddle.net/DyuaaP
Video commentary of this solution: https://youtu.be/6BsU1n1KTdo