0

我想知道如何通过按月分组和聚合计数来解决我的 Linq 问题。

以下是我的示例数据：

Code     CodeName   Color       Month
11111     One       Red          1
11111     One       Red          1
11111     One       Red          2
22222     Two       Green        2
33333     Three     Yellow       3
44444     Four      Blue         4
44444     Four      Blue         4
55555     Five      White        5

我想看到这样的结果：

Code      CodeName     Color     Count(Mont1)   Month2     Month3    Month4    Month5
11111       one        red           2            1          0         0         0
22222       two        Green         0            1          0         0         0
33333       three      Yellow        0            0          1         0         0
44444       four       Blue          0            0          0         2         0
55555       five       White         0            0          0         0         1
4

1 回答 1

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这是一个产生您想要的结果的示例

它的核心是这样的：

  • Code按属性对元素进行分组
  • Color按属性对每个分组中的元素进行分组
  • 处理每个分组，创建结果，其中每个MonthX属性设置为具有给定月份标识符的内部分组（按代码按颜色的项目）中的对象的计数

这专门处理问题中提供的 5 个月值，您可以将您喜欢的所有月份值拆分到结果对象上它们自己的属性中，或者如果需要其他值，则将其构建到月份索引与计数的字典中。

public enum Number
{
    One = 11111,
    Two = 22222,
    Three = 33333,
    Four = 44444,
    Five = 55555
}

public class Data
{
    public Number Code { get; set; }
    public string CodeName { get { return Enum.GetName(typeof(Number), Code); } }
    public ConsoleColor Color { get; set; }
    public int Month { get; set; }
}

public class Result
{
    public Number Code { get; set; }
    public string CodeName { get { return Enum.GetName(typeof(Number), Code); } }
    public ConsoleColor Color { get; set; }
    public int Month1 { get; set; }
    public int Month2 { get; set; }
    public int Month3 { get; set; }
    public int Month4 { get; set; }
    public int Month5 { get; set; }
}

class Program
{
    static void Main(string[] args)
    {
        var items = new Data[]
        {
            new Data{Code = Number.One, Color = ConsoleColor.Red, Month = 1},
            new Data{Code = Number.One, Color = ConsoleColor.Red, Month = 1},
            new Data{Code = Number.One, Color = ConsoleColor.Red, Month = 2},
            new Data{Code = Number.Two, Color = ConsoleColor.Green, Month = 2},
            new Data{Code = Number.Three, Color = ConsoleColor.Yellow, Month = 3},
            new Data{Code = Number.Four, Color = ConsoleColor.Blue, Month = 4},
            new Data{Code = Number.Four, Color = ConsoleColor.Blue, Month = 4},
            new Data{Code = Number.Five, Color = ConsoleColor.White, Month = 5},
        };

        var results = items.GroupBy(x => x.Code).Select(
            x => x.GroupBy(y => y.Color)
                  .Select(z => new Result
                  {
                      Code = x.Key,
                      Color = z.Key,
                      Month1 = z.Count(q => q.Month == 1),
                      Month2 = z.Count(q => q.Month == 2),
                      Month3 = z.Count(q => q.Month == 3),
                      Month4 = z.Count(q => q.Month == 4),
                      Month5 = z.Count(q => q.Month == 5),
                  }).ToList());

        var resultList = results.ToList();
    }
}
于 2013-06-26T20:01:55.367 回答