为什么这个for循环不处理完整的数据集？

Question

背景

我有一个事件的票证分配电子表格.电子表格的每一行都是名称和分配的故障单数量.

电子表格http://s3.amazonaws.com/twitpic/photos/full/120237739.png?AWSAccessKeyId=0ZRYP5X5F6FSMBCCSE82&Expires=1277404609&Signature=pGRx%2Fxcm3InEY2PyKd3k09hC7Xo%3D

我需要更改电子表格,以便每个票证在不同的行上复制一次,如下所示:

更改后的电子表格http://s3.amazonaws.com/twitpic/photos/full/120238390.png?AWSAccessKeyId=0ZRYP5X5F6FSMBCCSE82&Expires=1277404546&Signature=xrUAdzyIJWKGnrge%2FCD4EudiyX8%3D

我有一个宏来做这件事,但它表现出奇怪的行为

问题

宏不会遍历整个数据集.逐句通过代码显示,尽管刻意增加的值LastRow,For循环回路唯一指定原值但是很多次.LastRow每次迭代结束时的新值似乎被忽略.

这似乎特别奇怪,因为等效的Do While循环工作正常(请参阅下面的使用Do While循环的工作代码)

问题

为什么会出现问题部分(上面)中描述的行为,为什么它与等效结构不一致？

For循环宏

Sub InsertSurnames()

    Dim LastRow As Long
    Dim r As Long
    Dim surname As String
    Dim tickets As Integer
    Dim surnameCol As Integer
    Dim ticketCol As Integer
    Dim targetCol As Integer

    surnameCol = 1
    ticketCol = 3
    targetCol = 4
    LastRow = ActiveSheet.UsedRange.Rows(ActiveSheet.UsedRange.Rows.Count).Row

    For r = 1 To LastRow

        surname = Cells(r, surnameCol).Value
        tickets = Cells(r, ticketCol).Value


        If (Not (Len(surname) = 0)) Then

            Cells(r, targetCol).Value = surname

            For x = 1 To tickets - 1

                Cells(r + x, 1).EntireRow.Insert
                Cells(r + x, targetCol).Value = surname



            Next x

            LastRow = LastRow + tickets - 1

        End If


    Next r

End Sub

Do While循环宏

Sub InsertSurnames()

    Dim LastRow As Long
    Dim r As Long
    Dim surname As String
    Dim tickets As Integer
    Dim surnameCol As Integer
    Dim ticketCol As Integer
    Dim targetCol As Integer

    surnameCol = 1
    ticketCol = 3
    targetCol = 4
    LastRow = ActiveSheet.UsedRange.Rows(ActiveSheet.UsedRange.Rows.Count).Row
    r = 1

    Do While r <= LastRow

        surname = Cells(r, surnameCol).Value
        tickets = Cells(r, ticketCol).Value


        If (Not (Len(surname) = 0)) Then

            Cells(r, targetCol).Value = surname

            For x = 1 To tickets - 1

                Cells(r + x, 1).EntireRow.Insert
                Cells(r + x, targetCol).Value = surname



            Next x

            LastRow = LastRow + tickets - 1

        End If

        r = r + 1
    Loop

End Sub

Answer 1

编译器以不同方式交互'For'Loop构造,并使用不同的程序集调用将临时变量放入CPU缓存中,因此在每次迭代之后它不需要返回RAM来读取变量,它只需抓住它来自cpu的缓存.这是为了提高性能,这就是为什么'For'循环通常比'While'循环更快.'for'循环的限制变量仍然存在于内存中,但在每次迭代期间都不会读取它.因此,如果更改用于最初设置上限的变量,则循环仍将运行到您将其设置为的原始边界.while循环在每次迭代时检查其exit子句,而不缓存是变量.通常,当您有一定量的迭代时,应使用'For'循环,