Question

这是我的简单代码，我使用委托和lambda表达式来获取给定开始日期和结束日期的工作日。

我的朋友说他可以把整个程序写成一行。我该怎么做？

public delegate void GetWorkingDays(DateTime x,DateTime y);
class Program
{
    static void Main(string[] args)
    {
        var dt1 = new DateTime(2012, 10, 3);
        var dt2 = new DateTime(2013, 10, 3);
        System.Collections.ArrayList l = new ArrayList();
        GetWorkingDays d = (d1, d2) =>
        {
            while (d1.Date < d2.Date) 
            {
                if(d1.DayOfWeek == DayOfWeek.Saturday)
                {
                    d1 = d1.AddDays(2);
                    Console.WriteLine();
                }
                else
                {
                   Console.Write(d1.Day + "  ");
                    d1 = d1.AddDays(1);
                }
            } 
        };
        d(dt1, dt2);
    }
};

Answer 1

我不知道你怎么能在一行中做到这一点，因为它需要一行来定义委托，而一行最少要调用delagate。但是，这是平日和计算日期的一条线。

GetWorkingDays d = (dateFrom, dateTo) =>
        Enumerable
            .Range(0, (int)dateTo.Subtract(dateFrom).TotalDays + 1)
            .Select(x => dateFrom.AddDays(x))
            .Count(x => x.DayOfWeek != DayOfWeek.Saturday && x.DayOfWeek != DayOfWeek.Sunday);
Console.Writeline("Number of Weekdays is {0}",d(dateFrom, dateTo));

或者

 var days = Enumerable
            .Range(0, (int)d2.Subtract(d1).TotalDays + 1)
            .Select(x => d1.AddDays(x))
            .Count(x => x.DayOfWeek != DayOfWeek.Saturday && x.DayOfWeek != DayOfWeek.Sunday);

Answer 2

虽然这可能无法解答您的问题，但告诉您完全不应该这样做是非常重要的，原因有两个。

编写可读代码非常重要，您现有的代码尽可能好。复杂的单行程不仅会降低可读性，而且会使调试变得更难。整体维护是一场噩梦。
您的目标是带来副作用，而不是在计算后返回值。换句话说，您的代理人返回void。 Linq风格的查询不是这里的方式。

还有两个建议：

我在您的代码中看到了ArrayList。从.NET 2开始使用它是犯罪行为。See this.如果将其更改为List<T>，您将被誉为英雄。如果你的朋友聪明，他应该帮助你做这些基本的事情，而不是迂腐。
以Get...开头的名称不是返回（获取）任何内容（void）的方法（或委托）的好名称。我会称之为WorkingDaysPrinter左右。

只是为了它，你的答案将是：

WorkingDaysPrinter p = (d1, d2) => Enumerable.Range(0, d2.Subtract(d1).Days)
                                             .Select(x => d1.AddDays(x))
                                             .Where((x, i) => i == 0 || x.DayOfWeek != DayOfWeek.Sunday)
                                             .ToList()
                                             .ForEach(x =>
                                              {
                                                  if (x.DayOfWeek == DayOfWeek.Saturday)
                                                      Console.WriteLine();
                                                  else
                                                      Console.Write(x.Day + " ");
                                              });

稍微稍微分别编写查询，然后运行单独的foreach：

WorkingDaysPrinter p = (d1, d2) => 
{
    var query = Enumerable.Range(0, d2.Subtract(d1).Days)
                          .Select(x => d1.AddDays(x))
                          .Where((x, i) => i == 0 || x.DayOfWeek != DayOfWeek.Sunday);
    foreach (var day in query)
    {
        if (x.DayOfWeek == DayOfWeek.Saturday)
            Console.WriteLine();
        else
            Console.Write(x.Day + " ");
    });
}

从表面上看，我认为如果您的代表返回工作日列表会更好。类似的东西：

public delegate IEnumerable<DateTime> WorkingDaysGetter(DateTime x, DateTime y);

WorkingDaysGetter g = (d1, d2) => Enumerable.Range(0, d2.Subtract(d1).Days)
                                            .Select(x => d1.AddDays(x))
                                            .Where(x => x.DayOfWeek != DayOfWeek.Saturday && x.DayOfWeek != DayOfWeek.Sunday);
foreach (var day in g(dt1, dt2))
{
    Console.Write(x.Day + " ");
}

Answer 3

var count = Enumerable
        .Range(1, (int)y.Subtract(x).TotalDays)
        .Select(x => to.AddDays(x))
        .Count(x => x.DayOfWeek != DayOfWeek.Saturday && x.DayOfWeek != DayOfWeek.Sunday);

Answer 4

GetWorkingDays getWorkDays = (d1, d2) =>
    Enumerable.Range(1, (int)(dt2 - dt1).TotalDays)
        .Select(d => dt1.AddDays(d))
        .Where(d => d.DayOfWeek != DayOfWeek.Saturday && d.DayOfWeek != DayOfWeek.Sunday)
        .ToList()
        .ForEach(d => Console.Write(d.Day + " "));

在c＃中使用委托计算工作日数的最简单方法？

4 个答案: