按日期計算週數

Question

我試圖修復一個函數，該函數返回給定年份中的週數。

下面是它的外觀：

Function GetWeekNo(date) 
    weekOfYear = DatePart("ww", DateValue(date), vbMonday, vbFirstFourDays) 

    If weekOfYear > 52 Then 
     If DatePart("ww", DateValue(date) + 7, vbMonday, vbFirstFourDays) = 2 Then 
      weekOfYear = 1 
     End If 
    End If 

    GetWeekNo = weekOfYear 
End Function 

當此功能給出的日期2010年12月31日返回52共有53周，2010年

注：我沒有經典的ASP體驗，無論如何。

Answer 1

似乎取決於哪一週被認爲是「一年中的第一週」。

DatePart("ww", "12/31/2010", vbMonday) 
' returns 53 
' FirstWeekOfYear parameter defaults to vbFirstJan1 
' the week that contains January/01/2010 
' here, its the week starting on December/28/2009 

DatePart("ww", "12/31/2010", vbMonday, vbFirstFourDays) 
' returns 52 
' FirstWeekOfYear parameter set to vbFirstFourDays 
' the first week that has at least four days of the new year 
' here, its the week starting on January/04/2010 

DatePart("ww", "12/31/2010", vbMonday, vbFirstFullWeek) 
' returns 52 
' FirstWeekOfYear parameter set to vbFirstFullWeek 
' the first week that has full seven days of the new year 
' here, again, its the week starting on January/04/2010 

決定什麼是您對一年的第一週的定義，然後相應地使用DatePart函數。