菜鸟在LINQ，选择每个记录的第一个记录具有相同值

Question

我尝试我最好的学习LINQ，但进出口仍然有一个很难对其进行编码。就像这样，假设我有一个数据集或一个List，并且集合对象的名称或字段是列名称。

ID |日期|周一|星期二|星期三|星期四 |星期五|星期六|太阳|计数

1 | 01/05 | = 1 = | == 1 == | == 1 = | == 1 = = 1 = | = 0 = | = 0 == | == 5 < - （1）

2 | 02/02 | = 1 = | == 1 == | == 1 = | == 1 = = 1 = | = 0 = | = 0 == | == 5 ** | - （2）

3 | 03/02 | = 1 = | == 1 == | == 1 = | == 1 = = 1 = | = 0 = | = 0 == | == 5 ** | - （2）

4 | 04/06 | = 1 = | == 1 == | == 1 = | == 1 = = | 1 = | = 1 = | = 1 == | == 7 < - （1）

5 | 05/04 | = 1 = | == 1 == | == 1 = | == 1 = = | 1 = | = 1 = | = 1 == | == 7 ** | - （3）

6 | 06/01 | = 1 = | == 1 == | == 1 = | == 1 = = 1 = | = 1 = | = 1 == | == 7 ** | - （3）

7 | 07/06 | = 1 = | == 1 == | == 1 = | == 1 = = 0 = | = 0 = | = 0 == | == 4 < ----（1）

8 | 08/03 | = 1 = | == 1 == | == 1 = | == 1 = = | 0 = | = 0 = | = 0 == | == 4 ** | - （4）

9 | 09/07 | = 1 = | == 1 == | == 1 = | == 1 = = 0 = | = 0 = | = 0 == | == 4 ** | - （4）

10 | 10/05 | 1 = | == 1 == | == 1 = | == 1 = = 0 = | = 0 = | = 0 == | == 4 ** | - （4）

我要的是第一个获得所有的数字（1）的，则（2）因为他们属于第一个（1）。接下来是（3）的组，因为它们属于第二个（1）。最后一组（4）的是因为它们属于最后一个（1）。

请大家帮忙。

- 问题改写。 1.我怎么能得到第一组5，然后是7组，然后是4组？

Answer 1

看起来你想要按点数排序。

当你说“得到第一批5的”你是什么意思 - 你想获得什么样的数据？

UPDATE澄清

假设

public class Row 
{ 
    public int ID{get;set;} 
    public string Date{get;set;} 
    public int Count{get;set;} 
} 

Row r1 = new Row{ID=1, Date="01/01/01", Count=5}; 
Row r2 = new Row{ID=2, Date="01/02/01", Count=5}; 
Row r3 = new Row{ID=3, Date="01/03/01", Count=5}; 
Row r4 = new Row{ID=4, Date="01/04/01", Count=7}; 
Row r5 = new Row{ID=5, Date="01/05/01", Count=7}; 
Row r6 = new Row{ID=6, Date="01/06/01", Count=7}; 
Row r7 = new Row{ID=7, Date="01/07/01", Count=4}; 
Row r8 = new Row{ID=8, Date="01/08/01", Count=4}; 
Row r9 = new Row{ID=9, Date="01/09/01", Count=4}; 
Row r10 = new Row{ID=10, Date="01/01/01", Count=4}; 

List<Row> rows = new List<Row>{r1,r2,r3,r4,r5,r6,r7,r8,r9,r10}; 

后接着

// We will assign results of our query to this variable 
var result = 

// rows is a generic list of Row objects 
rows     

    // This splits the list into seperate categories organised by Count 
    // After the GroupBy, we have an IEnumerable<IGrouping<Int32, Row>> - that is, a collection of collections of items sharing a common key (in this case Count) 
    .GroupBy(r=>r.Count) // r is of type Row 

    // Now we are simply selecting the first item of each subgroup. 
    .Select(g=>g.First()) // g is IGrouping<Int32,Row>, g.First() is of type Row 
    ; 

给出

ID Date  Count 
    1 01/01/01 5 
    4 01/04/01 7 
    7 01/07/01 4