Question

我有一个包含2列的数据表：

GuitarBrand | Status
---------------------
Fender      | Sold
Fender      | In Stock
Gibson      | In Stock
Gibson      | In Stock

我想写一个linq查询来输出

 GuitarBrand | PercentSold | Sold/Total
 ---------------------------------------
 Fender      | 50%          | 1/2
 Gibson      | 100%         | 2/2

这是我到目前为止所拥有的：

var groupedtable = from b in table.AsEnumerable()
    group b by b.Field<"GuitarBrand"> into g
    select new ( GuitarBrand = g.Key, Perecent = (float)g.Count()/(float)g.key)

我从另一篇文章得到的但是它甚至没有接近工作，我得到一个无法转换字符串浮动。我试过看其他帖子但我找不到任何东西。

谢谢！

Answer 1

也许是这样的！

var groupedtable = from b in table.AsEnumerable()
    group b by b.Field<"GuitarBrand"> into g
    select new { 
     GuitarBrand = g.Key, 
     Perecent = g.Count(x=>x.Status.Eguals("Sold")/(float)g.Count()
    }

Answer 2

您可以使用以下（希望自我解释）查询：

var groupedtable = 
    from b in table.AsEnumerable()
    group b by b.Field<string>("GuitarBrand") into g
    let Total = g.Count()
    let Sold = g.Count(e => e.Field<string>("Status") == "Sold")
    let SoldPercent = (float)Sold / (float)Total
    select new
    {
        GuitarBrand = g.Key,
        PercentSold = SoldPercent.ToString("p"),
        TotalSold = Sold + "/" + Total
    };

Answer 3

这样的事情应该让你开始。在您的问题中，您的输出表是矛盾的。我假设你想要标记数据。

public static void Main()
{
    var guitars = new List<Guitar>()
    {
        new Guitar(){ Brand = "Fender", Status = Status.Sold },
        new Guitar(){ Brand = "Fender", Status = Status.InStock },
        new Guitar(){ Brand = "Gibson", Status = Status.InStock },
        new Guitar(){ Brand = "Gibson", Status = Status.InStock }
    };

    var query = guitars
                    .GroupBy(guitar => guitar.Brand)
                    .Select(group => new 
                    { 
                        GuitarBrand = group.Key, 
                        Sold = group.Where(guitar => guitar.Status == Status.Sold).Count(),
                        Total = group.Count()
                    })
                    .Select(_ => new 
                    {
                        _.GuitarBrand,
                        PercentSold = ((decimal)_.Sold / (decimal)_.Total) * 100,
                        SoldAndTotal = string.Format("{0}/{1}", _.Sold, _.Total)
                    });
}

class Guitar {
    public string Brand { get; set; }
    public Status Status { get; set; }
}

enum Status {
    Sold,
    InStock
}

Linq表组通过每列中的Perecentage

3 个答案: