求算法:一段时间段内的星期几到星期几的集合

[ohyear]

假设时间段为2009-04-01到2009-04-30.
我想得到这段时间内,每逢周一至周二的日期,要返回的结果集可以为DataTable(两列-周二日期和周三日期),或是二维数组(周二日期,周三日期)

另外:因为4月1号是星期三,所以周一至周二只有如下数据:
周一 周二
2009-04-06 2009-04-07
2009-04-13 2009-04-14
2009-04-20 2009-04-21
2009-04-27 2009-04-28

即,超过起始日期的星期几不算在内.

使用C#或是Sql给的算法都行....
在线急等..先谢了!

[xiaoqhuang]

declare @startDate datetime set @startDate='2009-04-01'
declare @endDate datetime set @endDate='2009-04-30'
declare @t table(Monday datetime,Tuesday datetime)
while dateadd(day,1,@startDate)<=@endDate
begin
if datepart(w,@startDate)=2
insert into @t select @startDate,dateadd(day,1,@startDate)
set @startDate=dateadd(day,1,@startDate)
end

--select * from @t

[ljhcy99]

DateTime d1 = new DateTime(2009, 4, 1);
DateTime d2 = new DateTime(2009, 4, 30);
DateTime d3 = d1;
DateTime d4 = d3;
//
DataTable table = new DataTable();
DataColumn col1 = new DataColumn("monday",Type.GetType("System.String"));
DataColumn col2 = new DataColumn("Tuseday", Type.GetType("System.String"));
table.Columns.Add(col1);
table.Columns.Add(col2);
//
while (DateTime.Compare(d3, d2) <= 0)
{
DayOfWeek week = d3.DayOfWeek;
if (week.ToString() == "Monday")
{
DataRow r = table.NewRow();
r[0] = d4.ToString();
r[1] = (d4.AddDays(1)).ToString();
table.Rows.Add(r);
}
d3 = d3.AddDays(1);
d4 = d3;
}

[dyshadow]

通用程序代码:

        private DataTable ReturnWeekDay(DateTime startDate, DateTime endDate, DayOfWeek startWeekDay, int daySpan)
        {
            DataTable tableToReturn = new DataTable("DayTable");
            for (int i = 0; i < daySpan; i++)
                tableToReturn.Columns.Add(new DataColumn());
            int iIndex = daySpan +1;
            DataRow newRow = null;
            for (DateTime currentDate = startDate; currentDate <= endDate; currentDate = currentDate.AddDays(1))
            {
                iIndex++;
                if (currentDate.DayOfWeek == startWeekDay)
                {
                    newRow= tableToReturn.Rows.Add (currentDate.ToString ("yyyy-MM-dd"));
                    iIndex = 0;
                }
                if (iIndex < daySpan && iIndex > 0)
                    newRow[iIndex] = currentDate.ToString("yyyy-MM-dd");
            }
            return tableToReturn;
        }

调用例

            DataTable dt = ReturnWeekDay(new DateTime(2009, 1, 1), new DateTime(2009, 2, 1), DayOfWeek.Monday, 2);

[liu4545533]

[Quote=引用 1 楼 xiaoqhuang 的回复:]
declare @startDate datetime set @startDate='2009-04-01'
declare @endDate datetime set @endDate='2009-04-30'
declare @t table(Monday datetime,Tuesday datetime)
while dateadd(day,1,@startDate) <=@endDate
begin
if datepart(w,@startDate)=2
insert into @t select @startDate,dateadd(day,1,@startDate)
set @startDate=dateadd(day,1,@startDate)
end

--select * from @t
[/Quote]
应该不要象仁兄这样做吧
Data类在c#里面可是超级强大的
其实可以用一个for循环 在循环内部判断是否为周一 和周二 并把其保存在不同的数组内部
这样很好实现

[dyshadow]

ReturnWeekDay(DateTime startDate, DateTime endDate, DayOfWeek startWeekDay, int daySpan)

startDate 开始日期，从哪个日期开始计算
endDate 结束日期，到该日期计算终止
startWeekDay 开始记录的日期是周几
daySpan 一共要记录几天

[wuyq11]

select datepart(weekday,getdate()) 为1 或2
select ( datepart(weekday,getdate()) + @@datefirst-1 ) % 7

[我姓区不姓区]

        static void Main(string[] args)
        {
            DataTable dt = GetDates(new DateTime(2009, 4, 1), new DateTime(2009, 4, 30));
            foreach (DataRow dr in dt.Rows)
                Console.WriteLine("Monday:{0},Tuesday:{1}", dr[0], dr[1]);
        }

        static DataTable GetDates(DateTime dtStart, DateTime dtEnd)
        {
            DataTable dt = new DataTable();
            dt.Columns.AddRange(new DataColumn[] { new DataColumn("Monday", typeof(string)), new DataColumn("Tuesday", typeof(string)) });
            DateTime time = dtStart;
            while (time.DayOfWeek != DayOfWeek.Monday)
                time = time.AddDays(1);
            dt.Rows.Add(time.ToString("yyyy-MM-dd"), time.AddDays(1).ToString("yyyy-MM-dd"));
            for (; time <= dtEnd; time = time.AddDays(7))
                dt.Rows.Add(time.ToString("yyyy-MM-dd"), time.AddDays(1) > dtEnd ? "" : time.AddDays(1).ToString("yyyy-MM-dd"));
            return dt;
        }
 /*
输出:
Monday:2009-04-06,Tuesday:2009-04-07
Monday:2009-04-06,Tuesday:2009-04-07
Monday:2009-04-13,Tuesday:2009-04-14
Monday:2009-04-20,Tuesday:2009-04-21
Monday:2009-04-27,Tuesday:2009-04-28
*/

[我姓区不姓区]

修改一下:

        static DataTable GetDates(DateTime dtStart, DateTime dtEnd)
        {
            DataTable dt = new DataTable();
            dt.Columns.AddRange(new DataColumn[] { new DataColumn("Monday", typeof(string)), new DataColumn("Tuesday", typeof(string)) });
            DateTime time = dtStart;
            while (time.DayOfWeek != DayOfWeek.Monday)
                time = time.AddDays(1);
            dt.Rows.Add(time.ToString("yyyy-MM-dd"), time.AddDays(1).ToString("yyyy-MM-dd"));
            for (time = time.AddDays(7); time <= dtEnd; time = time.AddDays(7))
                dt.Rows.Add(time.ToString("yyyy-MM-dd"), time.AddDays(1) > dtEnd ? "" : time.AddDays(1).ToString("yyyy-MM-dd"));
            return dt;
        }