[Solved] Ordering list of integers by the count of each element in C# [closed]

by


You can do:

  • Group by each item
  • Order by descending based on group count
  • select unique item based on group key

Like:

List<int> list = new List<int> { 1, 2, 3, 2, 1, 6, 2 };
var query = list.GroupBy(item => item)
                .OrderByDescending(grp => grp.Count())
                .Select(grp => grp.Key);


foreach (var item in query)
{
    Console.WriteLine(item);
}

EDIT:

If you don’t want unique item, but all the items based on their occurrence then use:

var query = list.GroupBy(item => item)
                .OrderByDescending(grp => grp.Count())
                .SelectMany(grp => grp);

SelectMany will flatten the list and give you an output like:

2
2
2
1
1
3
6

2

solved Ordering list of integers by the count of each element in C# [closed]