How to get frequency of elements from List in c#

Question

I am trying to get the frequency of elements stored in a list.

I am storing the following ID's in my list

ID
1
2
1
3
3
4
4
4

I want the following output:

ID| Count
1 | 2
2 | 1
3 | 2
4 | 3

In java you can do the following way.

for (String temp : hashset) 
    {
    System.out.println(temp + ": " + Collections.frequency(list, temp));
    }

Source:http://www.mkyong.com/java/how-to-count-duplicated-items-in-java-list/

How to get the frequency count of a list in c#?

Thanks.

Answer 1

using System.Linq;

List<int> ids = //

foreach(var grp in ids.GroupBy(i => i))
{
    Console.WriteLine("{0} : {1}", grp.Key, grp.Count());
}