计算一周内没有循环的工作天数？

Question

我需要计算给定结构的总工作天数，该结构表示一周中的哪几天工作以及从开始到现在。

我目前的算法是这样的：

protected int TotalWorkDays(DateTime From, DateTime dtTo,WorkedDays days)
    {
        int Days = 0;
        DayOfWeek DOW;
        for (DateTime curDate = From; curDate.Date <= dtTo.Date; curDate = curDate.AddDays(1))
        {
            DOW = curDate.DayOfWeek;
            if ((DOW == DayOfWeek.Sunday &  days.Sunday) |
                (DOW == DayOfWeek.Monday &  days.Monday) |
                (DOW == DayOfWeek.Tuesday &  days.Tuesday) |
                (DOW == DayOfWeek.Wednesday &  days.Wednesday) |
                (DOW == DayOfWeek.Thursday &  days.Thursday) |
                (DOW == DayOfWeek.Friday &  days.Friday) |
                (DOW == DayOfWeek.Saturday &  days.Saturday)
               )
            {
                Days += 1;
            }
        }
        return Days;
    }

我几乎肯定这可以在没有循环的情况下完成，但我似乎无法弄清楚。有人可以帮我找到更有效的算法吗？

Answer 1

求 From 和 To 日期之间的周数（使用减法和除法）。然后将其乘以每周工作的天数。对结束案例做一些减法（从/到日期在一周的中间）。

Answer 2

嗯嗯....

创建一个字典，从DayOfWeek（如果我没记错的话是int）到bool 然后......

var DaysWorked = (from dayoffset in Enumerable.Range(0, (To - From).TotalDays)
                  where WorkingDays[From.AddDays(dayoffset).DayOfWeek]
                  select dayoffset).Count();

虽然效率不高！

Answer 3

看看这个codeproject article，它解释了如何在不循环的情况下做到这一点；）

编辑：这是它使用的公式：

1. 以周为单位计算时间跨度数。叫它吧，W。
2. 从周数中减去第一周。 W= W-1
3. 将周数乘以每周的工作日数。 叫它，D。
4. 找出指定时间段内的假期。叫它，H。
5. 计算第一周的天数。就这样吧，SD。
6. 计算上周的天数。就这样吧，ED。
7. 总结所有的日子。 BD = D + SD + ED × H。

Answer 4

您可以利用一周中的几天每 7 天重复一次这一事实。以下是算法的基本概述：

1. 计算第一周的工作天数。
2. 计算最后一周的工作天数。
3. 计算中间的整周数，然后乘以一周的工作天数。
4. 将上述三个值相加。

Answer 5

var workDays = new DayOfWeek[]{ DayOfWeek.Monday, DayOfWeek.Tuesday};
var days = TotalWorkDays(new DateTime(2005,1,12), new DateTime(2005,3,15), workDays);

protected int TotalWorkDays(DateTime start, DateTime end, DayOfWeek[] workDays)
{
    var weeks = (int)Math.Floor((end - start).TotalDays / 7); 
    var days = weeks * workDays.Length;

    //Calc rest
    var d = start.AddDays(weeks * 7);
    while (d <= end)
    {
        if(workDays.Contains(d.DayOfWeek)) 
            days++;
        d = d.AddDays(1);

    }   
    return days;
}

Answer 6

您可以使用以下算法：

• 计算开始周的工作日（最多 7 次迭代）
• 计算开始/结束之间的周数以及工作日的多个周数
• 计算最后一周的工作日（最多 7 次迭代）

示例使用Time Period Library for .NET

的Week和DateDiff类

// ----------------------------------------------------------------------
public int CountWorkingDays( DateTime start, DateTime end, IList<DayOfWeek> workingDays )
{
  if ( workingDays.Count == 0 )
  {
    return 0;
  }

  Week startWeek = new Week( start );
  Week endWeek = new Week( end );
  int dayCount = 0;

  // start week
  DateTime currentDay = start.Date;
  while ( currentDay < startWeek.End )
  {
    if ( workingDays.Contains( currentDay.DayOfWeek ) )
    {
      dayCount++;
    }
    currentDay = currentDay.AddDays( 1 );
  }

  // between weeks
  DateDiff inBetweenWeekDiff = new DateDiff( startWeek.End, endWeek.Start );
  dayCount += inBetweenWeekDiff.Weeks * workingDays.Count;

  // end week
  currentDay = endWeek.Start.Date;
  while ( currentDay < end )
  {
    if ( workingDays.Contains( currentDay.DayOfWeek ) )
    {
      dayCount++;
    }
    currentDay = currentDay.AddDays( 1 );
  }

  return dayCount;
} // CountWorkingDays

用法：

// ----------------------------------------------------------------------
public void CountWorkingDaysSample()
{
  DayOfWeek[] workingDays = new [] { DayOfWeek.Monday, DayOfWeek.Tuesday };
  DateTime start = new DateTime( 2011, 3, 1 );
  DateTime end = new DateTime( 2011, 5, 1 );
  Console.WriteLine( "working days: {0}", CountWorkingDays( start, end, workingDays ) );
  // > working days: 19
} // CountWorkingDaysSample