拆分日期/周列表爲a和b周LINQ

Question

的datesList查詢只是一個日期時間值的列表。

隨着LINQ查詢/ GROUPBY I組所有那些屬於某一週在今年進入分組天。

Func<DateTime, int> weekProjector = d => 
CultureInfo.CurrentCulture.Calendar.GetWeekOfYear(d, CalendarWeekRule.FirstDay, DayOfWeek.Monday); 

var weeks = (from date in datesList group date by weekProjector(date.Date)).ToList(); 

讓我們假設星期收集包含8，並可以旋轉A和B星期。這意味着，如果該用戶與周開始通過值2的轉動傳遞該結果：

AA，BB，AA，BB（8周，每週一次旋轉是2）

AAAA，BBBB（8周，每週旋轉4）

我怎樣才能查詢周收集和組/項目或任何日期時間值到一個單獨weekListA/weekListB用考慮，其可以是從1的任何數量到8

UPDATE旋轉值：

最終狀態是2個列表A和B列表，每個列表包含周收集的日期時間值。

更新2：在這個樣本每週輪換將有因素4：這意味着我有4周A型，4周B型等

Answer 1

我希望我理解正確你。

給定一串日期，由今年星期分組：

// some testdata 
var datesList = Enumerable.Range(0, 8).Select (e => DateTime.Now.AddDays(7 * e)).ToList(); 

Func<DateTime, int> weekProjector = d => 
    CultureInfo.CurrentCulture.Calendar.GetWeekOfYear(d, CalendarWeekRule.FirstDay, DayOfWeek.Monday); 

var weeks = datesList.GroupBy(weekProjector).ToList(); 

你應該得到你想要通過這個查詢結果：

var result = weeks.OrderBy(w => w.Key) 
        .Select((g, i) => new {WeekType = (i/rotation) % 2, Week = g}) 
        .GroupBy(w => w.WeekType) 
        .ToList(); 

其中rotation是你的「旋轉」 （2或4）和2是要（組A和B => 2基團）基團的數目。

您可能要添加到Select的GroupBy後，只選擇你想要的數據，例如：

var weekA = result.Where(r => r.Key==0).Select(g => g).SelectMany(g => g).SelectMany(a => a.Week).ToList(); 
var weekB = result.Where(r => r.Key==1).Select(g => g).SelectMany(g => g).SelectMany(a => a.Week).ToList(); 

---

更可讀/通用的解決方案：

void Rotate<TResult, TGroup>(IEnumerable<TResult> datesList, Func<TResult, TGroup> grouper, int rotation, out List<TResult> listA, out List<TResult> listB) 
{ 
    listA = new List<TResult>(); 
    listB = new List<TResult>(); 

    var weeks = datesList.GroupBy(grouper).ToList(); 

    var c_rotation = 0; 
    var c_list = listA; 

    using (var en = weeks.GetEnumerator()) 
     while(en.MoveNext()) 
     { 
      c_list.AddRange((IGrouping<TGroup, TResult>)en.Current); 
      c_rotation++; 
      if (c_rotation == rotation) 
      { 
       c_rotation = 0; 
       c_list = c_list == listA ? listB : listA; 
      } 
     } 
} 

使用它喜歡：

List<DateTime> listA; 
List<DateTime> listB; 

Func<DateTime, int> weekProjector = d => 
    CultureInfo.CurrentCulture.Calendar.GetWeekOfYear(d, CalendarWeekRule.FirstDay, DayOfWeek.Monday); 

Rotate(datesList, weekProjector, 2, out listA, out listB); 

Answer 2

這可能是什麼你要找的，GroupBy Index % 2：

var abRotations = datesList 
    .GroupBy(d => CultureInfo.CurrentCulture.Calendar.GetWeekOfYear(d, CalendarWeekRule.FirstDay, DayOfWeek.Monday)) 
    .Select((wg, i) => new { WeekGroup = wg, Index = i }) 
    .GroupBy(x => x.Index % 2); 

List<DateTime> A_Rotation = abRotations.First().SelectMany(x => x.WeekGroup).ToList(); 
List<DateTime> B_Rotation = abRotations.Last().SelectMany(x => x.WeekGroup).ToList(); 

DEMO