Linq Select将为相似的值生成并列分数

本文关键字：Select 相似 Linq | 更新日期: 2023-09-27 18:15:33

我正在尝试生成一个基于分数的位置数字的简单联赛表。

。给定以下

List<Player> players = new List<Player>() {
    new Player { Name = "John", Score = 2 },
    new Player { Name = "Mary", Score = 1 },
    new Player { Name = "Bob", Score = 2 },
    new Player { Name = "Alice", Score = 3 },
};
var results = players
      .OrderByDescending(o => o.Score)
      .Select((v,i) => new { Name = v.Name, Score = v.Score, Position = i+1} );

结果将是。

Name  Score Pos
Alice 3     1 
John  2     2 
Bob   2     3 
Mary  1     4
相反，我希望结果是 
Name  Score Pos
Alice 3     1 
John  2     2 
Bob   2     2 <---- this guy is tied for second 
Mary  1     4 <---- this one still comes fourth

在Linq Select中是否有访问上一个或下一个元素的方法，以便您知道是增加还是减少索引值?

Linq Select将为相似的值生成并列分数

像这样的东西会对你有用吗?

  .Select((v,i) => new { Name = v.Name, 
                         Score = v.Score, 
                         Position = 
                            players.Count(p => p.Score > v.Score) + 1
                       }
         );

它听起来像你想做一个组by/selectmany

      var results = players
              .OrderByDescending(o => o.Score)
              .GroupBy(o => o.Score)
              .SelectMany((l, i) => l.Select(v => new { Name = v.Name, Score = v.Score, Position = i + 1 }));

您几乎有了索引选择语句的解决方案，但首先对数据集进行排序。

Edit:做了一个小的编辑，因为我把排序器的顺序搞错了，即它是按升序排序的。

List<Player> players = new List<Player>() {
    new Player { Name = "John", Score = 2 },
    new Player { Name = "Mary", Score = 1 },
    new Player { Name = "Bob", Score = 2 },
    new Player { Name = "Alice", Score = 3 },
};
players.Sort(delegate(Player x, Player y)
{
    return y.Score.CompareTo(x.Score);
});
var results = players
      .Select((v,i) => new { 
        Name = v.Name, 
        Score = v.Score, 
        Position = i+1, 
        TiedWithPrevious = i > 0 && players[i-1].Score == v.Score, 
        TiedWithNext = i < players.Count-1 && players[i+1].Score == v.Score } );
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