如何在C＃上对具有多个条件的列表进行排名

Question

I am trying to figure out how to rank a list with multiple conditions:

1. This is my list:

2. Let me explain the list above:

a. ' AreaCode ' is an unique ID for each group of the list.

b. I will rank the list based on highest value of Rank 1 (highlighted with yellow).

c. If Rank 1 has same value, I will find highest value of Rank 2 (highlighted by green).

d. If Rank 2 has same value, I will find highest value of Rank 3 (highlighted by blue).

e. In this case, there are same value for Rank 1 (7 and 7), so I will find the highest value for Rank 2, however the Rank 2 value also same (4 and 4), so I will find the highest value for Rank 3 (1 and 2).

f. So ' Ranking ' column is the result that I want to achieve, which is a list with these value:
[1, 1, 1, 3, 3, 3, 2, 2, 2, 2, 2, 2, 1, 1, 1, 3, 3, 3] .

3. Last time I can do but with simple scenario (there are no Rank 1, Rank 2 or Rank 3) using this code:

    var rankings = myIndexList.GroupBy(x => x) .OrderByDescending(g => g.Key) .Select((g, i) => new { Key = g.Key, Rank = i + 1 }) .ToDictionary(x => x.Key, x => x.Rank); var output = myIndexList.Select(x => new { Col1 = x, Rank = rankings[x] }) .ToList(); 

Any ideas to achieve the result on ' Ranking ' column?

Thank You!

Answer 1

I recommend this.

public class Item
{
    public string Name { get; set; }
    public int Value { get; set; }
}

/////
var list = new List<(Item Col1, int Rank)>();

var nameGroup = items.GroupBy(i => i.Name);
var sorted = nameGroup.OrderBy(i => i.Key);

foreach (var group in sorted)
{
    int ranking = 1;
    foreach (var item in group.OrderByDescending(i => i.Value))
    {
        list.Add((Col1: item, Rank: ranking++));
    }
}