如何在linq DateTime中正确设置变量？
如何在linq DateTime中正确设置变量？
提问于 2019-06-24 02:42:42
我是编程新手，也是C#新手。最近，我一直在做一个从csv格式中过滤数据的工具。我发现使用linq是我最好的选择。正如你所看到的，这一段下面的代码运行良好，但我想让它更灵活。我想问的是，有没有更聪明的方法使：DateTime(s.Date.Year, s.Date.Month, s.Date.Day, s.Date.Hour, s.Date.Minute, s.Date.Second)作为一个变量，用户可以选择它作为一个选项。现在，我已经编写了代码，其中用户选择选项，并基于变量：PublicVariables.customfiltersetting == 5我正在使用条件来设置我的排序...下面是代码的其余部分：
using (var writer = new StreamWriter(outputname))
{
var ordering = from s in Filter.FullData()
group s by new DateTime(s.Date.Year, s.Date.Month, s.Date.Day, s.Date.Hour, s.Date.Minute, s.Date.Second)
into g
let count = g.Count()
orderby g.Key descending
select new {Date = g.Key, Column = g.Average(s => s.Column), Count = count};
if (PublicVariables.customfiltersetting == 0)
{
ordering = from s in Filter.FullData()
group s by new DateTime(s.Date.Year, s.Date.Month, s.Date.Day, s.Date.Hour, s.Date.Minute, s.Date.Second)
into g
let count = g.Count()
orderby g.Key descending
select new {Date = g.Key, Column = g.Average(s => s.Column), Count = count};
}
else if (PublicVariables.customfiltersetting == 1)
{
ordering = from s in Filter.FullData()
group s by new DateTime(s.Date.Year, s.Date.Month, s.Date.Day, s.Date.Hour, s.Date.Minute, 0)
into g
let count = g.Count()
orderby g.Key descending
select new {Date = g.Key, Column = g.Average(s => s.Column), Count = count};
}
else if (PublicVariables.customfiltersetting == 2)
{
ordering = from s in Filter.FullData()
group s by new DateTime(s.Date.Year, s.Date.Month, s.Date.Day, s.Date.Hour, 0, 0)
into g
let count = g.Count()
orderby g.Key descending
select new {Date = g.Key, Column = g.Average(s => s.Column), Count = count};
}
else if (PublicVariables.customfiltersetting == 3)
{
ordering = from s in Filter.FullData()
group s by new DateTime(s.Date.Year, s.Date.Month, s.Date.Day, 0, 0, 0)
into g
let count = g.Count()
orderby g.Key descending
select new {Date = g.Key, Column = g.Average(s => s.Column), Count = count};
}
else if (PublicVariables.customfiltersetting == 4)
{
ordering = from s in Filter.FullData()
group s by new DateTime(s.Date.Year, s.Date.Month, 0, 0, 0, 0)
into g
let count = g.Count()
orderby g.Key descending
select new {Date = g.Key, Column = g.Average(s => s.Column), Count = count};
}
else if (PublicVariables.customfiltersetting == 5)
{
ordering = from s in Filter.FullData()
group s by new DateTime(s.Date.Year, 0, 0, 0, 0, 0)
into g
let count = g.Count()
orderby g.Key descending
select new {Date = g.Key, Column = g.Average(s => s.Column), Count = count};
}
else
{
ordering = from s in Filter.FullData()
group s by new DateTime(s.Date.Year, s.Date.Month, s.Date.Day, s.Date.Hour, s.Date.Minute, 0)
into g
let count = g.Count()
orderby g.Key descending
select new {Date = g.Key, Column = g.Average(s => s.Column), Count = count};
}
foreach (var s in ordering)
{
Console.WriteLine(s.Date + "\t" + s.Column + "\t " + s.Average + "\t " + s.Count);
writer.WriteLine("Date: " + strings.Value + " Value: " + strings.Average.ToString("0.00") + "\t" +
" Count: " + strings.Count);
}
}回答 1
Stack Overflow用户
回答已采纳
发布于 2019-06-24 06:20:34
暂时忽略代码中的问题，比如未声明的strings变量，以及使用非法的0值作为DateTime的月份和月日值的默认值，您可能会发现代码读起来会更好一些：
Func<MyDataType, DateTime> selectKey;
switch (PublicVariables.customfiltersetting)
{
case 0:
goto default;
case 1:
selectKey = s => new DateTime(s.Date.Year, s.Date.Month, s.Date.Day, s.Date.Hour, s.Date.Minute, 0);
break;
case 2:
selectKey = s => new DateTime(s.Date.Year, s.Date.Month, s.Date.Day, s.Date.Hour, 0, 0);
break;
case 3:
selectKey = s => new DateTime(s.Date.Year, s.Date.Month, s.Date.Day, 0, 0, 0);
break;
case 4:
selectKey = s => new DateTime(s.Date.Year, s.Date.Month, 1, 0, 0, 0);
break;
case 5:
selectKey = s => new DateTime(s.Date.Year, 1, 1, 0, 0, 0);
break;
default:
selectKey = s => new DateTime(s.Date.Year, s.Date.Month, s.Date.Day, s.Date.Hour, s.Date.Minute, s.Date.Second);
break;
}
var ordering = from s in Filter.FullData()
group s by selectKey(s) into g
let count = g.Count()
orderby g.Key descending
select new { Date = g.Key, Column = g.Average(s => s.Column), Count = count };页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/56726846
复制相关文章
相似问题