每个更改行列的LINQ和DateTime计算 [英] LINQ and DateTime Calculation for every change row column

问题描述

大家好，
我遇到一个需要知道响应的问题.
我的第一个问题是，我是LINQ语言的新手，所以我无法对此进行更深入的介绍.
我的第二个问题是我有一些数据，例如以下内容(数千行和数百个csv文件):

Hi folks,
I am encountering on a problem that I need to know the response.
My first problem is that I am new on LINQ language so I cannot go deeper on that yet.
My second problem is that I have some bunch of data like following (thousands of row and hundreds of csv files) :

00:00:28	TEST1
00:00:30	TEST1
00:00:34	TEST1
00:00:31	TEST1
00:00:34	TEST1
00:02:48	TEST2
00:03:24	TEST2
00:02:48	TEST2
00:02:56	TEST3
12:58:20	TEST4
08:10:41	TEST4
07:57:38	TEST4
12:58:20	TEST4
00:01:49	TEST5
00:01:04	TEST5
00:01:49	TEST5
00:01:04	TEST5
00:01:49	TEST5

两列用制表符"分隔.
我需要的是计算:
-平均，
-最大值
第二列的每次更改.
的意思是:
-TEST1:

Two columns separated by "tab".
What I need to have is calculate the :
- average,
- maximum
of every change of the second column.
Means for :
- TEST1 :

* average: 00:00:31
* maximum: 00:00:34

-TEST2:

- TEST2 :

* average: 00:03:00
* maximum: 00:03:24

-TEST3:

- TEST3 :

* average: 00:02:56
* maximum: 00:02:56

-TEST4:

- TEST4 :

* average: 10:31:15
* maximum: 12:58:20

-TEST5:

- TEST5 :

* average: 00:01:31
* maximum: 00:01:49

就像在excel软件中每次更改列时计算小计一样，但是在我的情况下，我想将LINQ/DataTable与C#一起使用.

有谁能指出我这样做的正确方法?

到目前为止，我所做的就是:

Like calculating the subtotal at each change of a column in excel software, but in my case I want to use LINQ/DataTable with C#.

Is anyone can point me to the right way to do that ?

What I have done so far from here is this :

var qry = from row in dtTbl.AsEnumerable()
                              group row by row.Field<string>("t_Source") into grp
                              select new
                                         {
                                             sum = grp.Sum(r=>r.Field<int>("id"))
                };
                    foreach (var grp in qry)
                    {
                        Console.Write(String.Format("Sum:{0}", grp.sum));
                    }

只是为了测试，但没有输出正确的结果，我得到了错误.

预先感谢您的帮助.

Just for test but did not output the right result, I got error.

Thanks in advance for your help.

推荐答案

如果试图模拟您的代码(和DataTable).我遇到的问题是id字段(我假设它是包含时间的字段)包含datetime值而不是int.因此，为了计算总和，我将其更改为

If tried to simulate your code (and DataTable). The problem I ran into was that id field (I assume that it is the field containing the time) contains a datetime value instead off a int. So to calculate the sum, I changed it into

var qry = from row in dtTbl.AsEnumerable()
    group row by row.Field<string>("t_Source") into grp
    select new
    {
       sum = grp.Sum(r=>r.Field<datetime>("id").TimeOfDay.TotalSeconds)
    };

将代码重写为您可以使用的解决方案，如下所示:

Rewriting the code to a solution you could use, could look something like this:

var qry = from row in dtTbl.AsEnumerable()
    group row by row.Field<string>("t_Source") into grp
    select new
    {
        source = grp.Key,
        avg = new TimeSpan(0, 0, (int)(grp.Average(r => r.Field<datetime>("id").TimeOfDay.TotalSeconds))),
        max = new TimeSpan(0, 0, (int)(grp.Max(r => r.Field<datetime>("id").TimeOfDay.TotalSeconds)))
    };

foreach (var grp in qry2)
{
    Console.WriteLine(String.Format("Source {0}: average = {1}, max = {2}", grp.source, grp.avg, grp.max));
}

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