linq“让”分裂，然后顺序升序

Question

我有这些数据，我正在使用linqToExcel：

我试图将通货膨胀除以GDP ...然后命令它们上升，但我无法做到正确。

    var people = from x in excel.Worksheet<CountryEconomics>("Sheet1")
                 let c = x.Inflation / x.GDP
                 orderby c ascending 
                 select c;

我得到了输出：

12
6
4
3
2
2

无论我在查询中放置升序还是降序。如何获得数据上升？即。

2
2
3
4
6
12

Answer 1

MSDN orderby clause

var people = from x in excel.Worksheet<CountryEconomics>("Sheet1")
             let c = x.Inflation / x.GDP
             orderby c
             select c;  

---

我无法只使用数组重现：

var economics = new[]
    {
        new {Country = "USA", GDP = 1, Inflation = 12},
        new {Country = "GB", GDP = 2, Inflation = 12},
        new {Country = "JPN", GDP = 3, Inflation = 12},
        new {Country = "GER", GDP = 4, Inflation = 12},
        new {Country = "CHI", GDP = 5, Inflation = 12},
        new {Country = "CAN", GDP = 6, Inflation = 12},
    };

var people = from x in economics
             let c = x.Inflation/x.GDP
             orderby c
             select c;

// without "orderby c":  12, 6, 4, 3, 2, 2
// with "orderby c":  2, 2, 3, 4, 6, 12
Console.WriteLine(string.Join(", ", people));

---

这可能是Linq-to-Excel的一个缺陷。 （我无法对此进行测试。）

如果是这种情况，您可以强制进行评估（通过下面的.ToArray()），然后对其进行排序。作为使用LINQ的任何静态数据的使用者，我期望 ToArray调用是不必要的。

var people = from x in economics
             let c = x.Inflation/x.GDP
             select c;

var sorted = people.ToArray().OrderBy(c => c);
Console.WriteLine(string.Join(", ", sorted));

Answer 2

如果你只想按Inflation / GDP排序，你可以这样做：

var people = from x in excel.Worksheet<CountryEconomics>("Sheet1")
             orderby x.Inflation / x.GDP
             select x;

或者用流利的语法：

var people = excel.Worksheet<CountryEconomics>("Sheet1")
                  .OrderBy(x => x.Inflation / x.GDP);

我不确定，但您可能需要跳过第一行（包含标题）。

var people = excel.Worksheet<CountryEconomics>("Sheet1")
                  .Skip(1).OrderBy(x => x.Inflation / x.GDP);

Answer 3

现在，我只是猜测，但也许添加一些演员阵容会让它发挥作用：

var people = from x in excel.Worksheet<CountryEconomics>("Sheet1")
             let c = ((double)x.Inflation) / ((double)x.GDP)
             orderby c ascending 
             select c;

然而，如果那也失败了 - 如果你先把它列为一个列表会发生什么：

var people = from x in excel.Worksheet<CountryEconomics>("Sheet1").ToList()
             let c = ((double)x.Inflation) / ((double)x.GDP)
             orderby c ascending
             select c;

如果仍然失败：

var people = from x in excel.Worksheet<CountryEconomics>("Sheet1")
             let c = ((double)x.Inflation) / ((double)x.GDP)
             select c;

var peopleList = people.ToList().OrderBy(p => p);

希望这能完成......