你是怎么在VBA找到Leapyear的？

Question

什么是VBA中IsLeapYear函数的良好实现？

编辑:我运行if-then和DateSerial实现,迭代包含在计时器中,并且DateSerial平均更快1-2毫秒(5次运行300次迭代,1个平均单元工作表公式也工作).

Answer 1

Public Function isLeapYear(Yr As Integer) As Boolean  

    ' returns FALSE if not Leap Year, TRUE if Leap Year  

    isLeapYear = (Month(DateSerial(Yr, 2, 29)) = 2)  

End Function  

我最初从Chip Pearson的Excel网站上获得了这个功能.

皮尔逊的网站

Answer 2

public function isLeapYear (yr as integer) as boolean
    isLeapYear   = false
    if (mod(yr,400)) = 0 then isLeapYear  = true
    elseif (mod(yr,100)) = 0 then isLeapYear  = false
    elseif (mod(yr,4)) = 0 then isLeapYear  = true
end function

维基百科更多... http://en.wikipedia.org/wiki/Leap_year

Answer 3

如果效率是一个考虑因素而且预期年份是随机的,那么首先做最常见的案例可能会稍好一些:

public function isLeapYear (yr as integer) as boolean
    if (mod(yr,4)) <> 0 then isLeapYear  = false
    elseif (mod(yr,400)) = 0 then isLeapYear  = true
    elseif (mod(yr,100)) = 0 then isLeapYear  = false
    else isLeapYear = true
end function