如何获得“日期”?使用Linq计算(姓名,课程)组的最高/最低分数
本文关键字:课程 最低分 姓名 日期 何获得 使用 计算 Linq | 更新日期: 2023-09-27 18:18:42
数据表有4列
Name Course Date Score
Alex Math 10/15 90
Bob Chem 10/28 91
Alex Math 10/29 91
Alex Math 12/08 89
Bob Chem 11/23 97
Alex Chem 10/16 94
Alex Chem 10/30 92
Bob Chem 10/01 94
我可以获得每个对应(姓名、课程)组的所有max、min和ave分数,但是如何获取和输出对应max/min分数的"Max_Date"answers"Min_Date"项呢?如
Name Course Max_Date Max Min_Date Min Average
Alex Math 10/29 91 12/08 89 90
Alex Chem 10/16 94 10/30 92 93
Bob Chem 11/23 97 10/28 91 94
下面是我的代码,我如何获取日期项目?
var result = dt.AsEnumerable()
.GroupBy(r => new
{
name = r.Field<string>("Name"),
course = r.Field<string>("Course")
})
.Select(g => new
{
name = g.Key.name,
course = g.Key.course,
max = g.Max(r => r.Field<int>("score")),
min = g.Min(r => r.Field<int>("score")),
ave = g.Average(r => r.Field<int>("score"))
}).Distinct().ToList();
foreach (var item in result)
Console.WriteLine(s.name + "'t" + s.course + "'t" + s.max + "'t" + s.min + "'t" + (int)s.ave);
var result = dt.AsEnumerable()
.GroupBy(r => new
{
name = r.Field<string>("Name"),
course = r.Field<string>("Course")
})
.Select(g => new
{
name = g.Key.name,
course = g.Key.course,
max = g.Max(r => r.Field<int>("score")),
Max_Date = g.FirstOrDefault(x=> x.Field<int>("score")==g.Max(r => r.Field<int>("score")).Date ,
Min_Date= g.FirstOrDefault(x=> x.Field<int>("score")==g.Min(r => r.Field<int>("score")).Date ,
min = g.Min(r => r.Field<int>("score")),
ave = g.Average(r => r.Field<int>("score"))
}).Distinct().ToList();
foreach (var item in result)
Console.WriteLine(s.name + "'t" + s.course + "'t" + s.max + "'t" + s.min + "'t" + (int)s.ave);
像这样:
dt.AsEnumerable()
.GroupBy(r => new
{
name = r.Field<string>("Name"),
course = r.Field<string>("Course")
})
.Select(g => new {
Group = g,
MaxEntry = g.First(gg => gg.Field<int>("score") == g.Max(r => r.Field<int>("score")))
})
.Select(g => new
{
name = g.Group.Key.name,
course = g.Group.Key.course,
max = g.MaxEntry.Field<int>("score"),
maxdate = g.MaxEntry.Field<datetime>("date"),
min = g.Group.Min(r => r.Field<int>("score")),
ave = g.Group.Average(r => r.Field<int>("score"))
}).Distinct().ToList();
注意:未经测试,但应该给你一个想法