在VBA (Excel)中减去范围

Question

我想做的是

我正在尝试编写函数以减去Excel 。它应该有两个输入参数:范围A和范围B。它应该返回一个范围对象，该对象由区域A的一部分而不是范围B的一部分(如集减法中的单元格组成)。

我试过的

我在web上看到了一些使用临时工作表来完成此操作的示例(快速，但可能会引入一些受保护的工作簿之类的问题)，以及其他一些通过第一个范围逐个单元格检查与第二个工作表的交叉点的示例(非常慢)。

经过一些思考之后，我想出了这个代码{1}，它工作得更快，但仍然很慢。从表示整个工作表的范围中减去1到5分钟，取决于第二个范围的复杂程度。

当我查看该代码，试图找到使其更快的方法时，我看到了应用divide-and-conquer范例的可能性，我做了{2}。但这反而使我的代码变慢了。我不太喜欢CS，所以我可能做错了什么，或者这个算法根本不是分而治之应该使用的算法，我不知道。

我也尝试过使用大部分递归重写它，但这需要花费很长时间才能完成，或者(更多的时候)已经从Stack Space错误中抛出。我没有保存密码。

唯一(稍微)成功的改进是添加了一个翻转开关{3}并先遍历行，然后(在下一次调用中)通过列，而不是在相同的调用中同时进行，但效果并不像我所希望的那样好。现在我看到，尽管我们没有在第一个调用中遍历所有行，但在第二个调用中，我们仍然循环遍历第一个调用中相同数量的行，只有这些行稍微短一些:)

我希望在改进或重写此功能方面有任何帮助，谢谢！

基于https://stackoverflow.com/users/4280接受的答案的解决方案

迪克·库斯莱卡，非常感谢你的回答！我想我会用它做一些修改：

• 去掉全局变量(mrBuild)
• 修正“一些重叠”条件以排除“不重叠”的情况
• 添加了更复杂的条件来选择是从上到下还是从左到右分割范围。

通过这些修改，代码在大多数常见情况下运行得非常快。正如已经指出的那样，棋盘式的巨大范围仍将是缓慢的，我同意这是不可避免的。

我认为这段代码还有改进的余地，我会更新这篇文章，以防我修改它。

改进的可能性：

• 选择如何拆分范围(按列或按行)的启发式方法

{0}解决方案代码

Public Function SubtractRanges(rFirst As Range, rSecond As Range) As Range
'
' Returns a range of cells that are part of rFirst, but not part of rSecond
' (as in set subtraction)
'
' This function handles big input ranges really well!
'
' The reason for having a separate recursive function is
' handling multi-area rFirst range
'
    Dim rInter As Range
    Dim rReturn As Range
    Dim rArea As Range

    Set rInter = Intersect(rFirst, rSecond)
    Set mrBuild = Nothing

    If rInter Is Nothing Then 'no overlap
        Set rReturn = rFirst
    ElseIf rInter.Address = rFirst.Address Then 'total overlap
        Set rReturn = Nothing
    Else 'partial overlap
        For Each rArea In rFirst.Areas
            Set mrBuild = BuildRange(rArea, rInter) 'recursive
        Next rArea
        Set rReturn = mrBuild
    End If

    Set SubtractRanges = rReturn
End Function


Private Function BuildRange(rArea As Range, rInter As Range, _
Optional mrBuild As Range = Nothing) As Range
'
' Recursive function for SubtractRanges()
'
' Subtracts rInter from rArea and adds the result to mrBuild
'
    Dim rLeft As Range, rRight As Range
    Dim rTop As Range, rBottom As Range
    Dim rInterSub As Range
    Dim GoByColumns As Boolean

    Set rInterSub = Intersect(rArea, rInter)
    If rInterSub Is Nothing Then 'no overlap
        If mrBuild Is Nothing Then
            Set mrBuild = rArea
        Else
            Set mrBuild = Union(mrBuild, rArea)
        End If
    ElseIf Not rInterSub.Address = rArea.Address Then 'some overlap
        If Not rArea.Cells.CountLarge = 1 Then 'just in case there is only one cell for some impossible reason

            ' Decide whether to go by columns or by rows
            ' (helps when subtracting whole rows/columns)
            If Not rInterSub.Columns.Count = rArea.Columns.Count And _
            ((Not rInterSub.Cells.CountLarge = 1 And _
            (rInterSub.Rows.Count > rInterSub.Columns.Count _
            And rArea.Columns.Count > 1) Or (rInterSub.Rows.Count = 1 _
            And Not rArea.Columns.Count = 1)) Or _
            (rInterSub.Cells.CountLarge = 1 _
            And rArea.Columns.Count > rArea.Rows.Count)) Then
                    GoByColumns = True
            Else
                    GoByColumns = False
            End If

            If Not GoByColumns Then
                Set rTop = rArea.Resize(rArea.Rows.Count \ 2) 'split the range top to bottom
                Set rBottom = rArea.Resize(rArea.Rows.Count - rTop.Rows.Count).Offset(rTop.Rows.Count)
                Set mrBuild = BuildRange(rTop, rInterSub, mrBuild) 'rerun it
                Set mrBuild = BuildRange(rBottom, rInterSub, mrBuild)
            Else
                Set rLeft = rArea.Resize(, rArea.Columns.Count \ 2) 'split the range left to right
                Set rRight = rArea.Resize(, rArea.Columns.Count - rLeft.Columns.Count).Offset(, rLeft.Columns.Count)
                Set mrBuild = BuildRange(rLeft, rInterSub, mrBuild) 'rerun it
                Set mrBuild = BuildRange(rRight, rInterSub, mrBuild)
            End If
        End If
    End If

    Set BuildRange = mrBuild
End Function

问题中提到的其他代码

{1}初始代码(逐行、逐列)

Function SubtractRanges(RangeA, RangeB) As Range
'
' Returns a range of cells that are part of RangeA, but not part of RangeB
'
' This function handles big RangeA pretty well (took less than a minute
' on my computer with RangeA = ActiveSheet.Cells)
'
    Dim CommonArea As Range
    Dim Result As Range

    Set CommonArea = Intersect(RangeA, RangeB)
    If CommonArea Is Nothing Then
        Set Result = RangeA
    ElseIf CommonArea.Address = RangeA.Address Then
        Set Result = Nothing
    Else
        'a routine to deal with A LOT of cells in RangeA
        'go column by column, then row by row
        Dim GoodCells As Range
        Dim UnworkedCells As Range

        For Each Area In RangeA.Areas
            For Each Row In Area.Rows
                Set RowCommonArea = Intersect(Row, CommonArea)
                If Not RowCommonArea Is Nothing Then
                    If Not RowCommonArea.Address = Row.Address Then
                        Set UnworkedCells = AddRanges(UnworkedCells, Row)
                    End If
                Else
                    Set GoodCells = AddRanges(GoodCells, Row)
                End If
            Next Row

            For Each Column In Area.Columns
                Set ColumnCommonArea = Intersect(Column, CommonArea)
                If Not ColumnCommonArea Is Nothing Then
                    If Not ColumnCommonArea.Address = Column.Address Then
                        Set UnworkedCells = AddRanges(UnworkedCells, Column)
                    End If
                Else
                    Set GoodCells = AddRanges(GoodCells, Column)
                End If
            Next Column
        Next Area

        If Not UnworkedCells Is Nothing Then
            For Each Area In UnworkedCells
                Set GoodCells = AddRanges(GoodCells, SubtractRanges(Area, CommonArea))
            Next Area
        End If

        Set Result = GoodCells
    End If

    Set SubtractRanges = Result
End Function

{2}划分和征服

Function SubtractRanges(RangeA, RangeB) As Range
'
' Returns a range of cells that are part of RangeA, but not part of RangeB
'
    Dim CommonArea As Range
    Dim Result As Range

    Set CommonArea = Intersect(RangeA, RangeB)
    If CommonArea Is Nothing Then
        Set Result = RangeA
    ElseIf CommonArea.Address = RangeA.Address Then
        Set Result = Nothing
    Else
        'a routine to deal with A LOT of cells in RangeA
        'go column by column, then row by row
        Dim GoodCells As Range
        Dim UnworkedCells As Range

        For Each Area In RangeA.Areas

            RowsNumber = Area.Rows.Count
            If RowsNumber > 1 Then
                Set RowsLeft = Range(Area.Rows(1), Area.Rows(RowsNumber / 2))
                Set RowsRight = Range(Area.Rows(RowsNumber / 2 + 1), Area.Rows(RowsNumber))
            Else
                Set RowsLeft = Area
                Set RowsRight = CommonArea.Cells(1, 1) 'the next best thing to Nothing - will end its cycle rather fast and won't throw an error with For Each statement
            End If
            For Each Row In Array(RowsLeft, RowsRight)
                Set RowCommonArea = Intersect(Row, CommonArea)
                If Not RowCommonArea Is Nothing Then
                    If Not RowCommonArea.Address = Row.Address Then
                        Set UnworkedCells = AddRanges(UnworkedCells, Row)
                    End If
                Else
                    Set GoodCells = AddRanges(GoodCells, Row)
                End If
            Next Row

            ColumnsNumber = Area.Columns.Count
            If ColumnsNumber > 1 Then
                Set ColumnsLeft = Range(Area.Columns(1), Area.Columns(ColumnsNumber / 2))
                Set ColumnsRight = Range(Area.Columns(ColumnsNumber / 2 + 1), Area.Columns(ColumnsNumber))
            Else
                Set ColumnsLeft = Area
                Set ColumnsRight = CommonArea.Cells(1, 1)
            End If
            For Each Column In Array(ColumnsLeft, ColumnsRight)
                Set ColumnCommonArea = Intersect(Column, CommonArea)
                If Not ColumnCommonArea Is Nothing Then
                    If Not ColumnCommonArea.Address = Column.Address Then
                        Set UnworkedCells = AddRanges(UnworkedCells, Column)
                    End If
                Else
                    Set GoodCells = AddRanges(GoodCells, Column)
                End If
            Next Column
        Next Area

        If Not UnworkedCells Is Nothing Then
            For Each Area In UnworkedCells
                Set GoodCells = AddRanges(GoodCells, SubtractRanges(Area, CommonArea))
            Next Area
        End If

        Set Result = GoodCells
    End If

    Set SubtractRanges = Result
End Function

{3}初始代码+翻转开关(逐行或逐列交替)

Function SubtractRanges(RangeA, RangeB, Optional Flip As Boolean = False) As Range
'
' Returns a range of cells that are part of RangeA, but not part of RangeB
'
' This function handles big RangeA pretty well (took less than a minute
' on my computer with RangeA = ActiveSheet.Cells)
'
    Dim CommonArea As Range
    Dim Result As Range

    Set CommonArea = Intersect(RangeA, RangeB)
    If CommonArea Is Nothing Then
        Set Result = RangeA
    ElseIf CommonArea.Address = RangeA.Address Then
        Set Result = Nothing
    Else
        'a routine to deal with A LOT of cells in RangeA
        'go column by column, then row by row
        Dim GoodCells As Range
        Dim UnworkedCells As Range

        For Each Area In RangeA.Areas
            If Flip Then
                For Each Row In Area.Rows
                    Set RowCommonArea = Intersect(Row, CommonArea)
                    If Not RowCommonArea Is Nothing Then
                        If Not RowCommonArea.Address = Row.Address Then
                            Set UnworkedCells = AddRanges(UnworkedCells, Row)
                        End If
                    Else
                        Set GoodCells = AddRanges(GoodCells, Row)
                    End If
                Next Row
            Else
                For Each Column In Area.Columns
                    Set ColumnCommonArea = Intersect(Column, CommonArea)
                    If Not ColumnCommonArea Is Nothing Then
                        If Not ColumnCommonArea.Address = Column.Address Then
                            Set UnworkedCells = AddRanges(UnworkedCells, Column)
                        End If
                    Else
                        Set GoodCells = AddRanges(GoodCells, Column)
                    End If
                Next Column
            End If
        Next Area

        If Not UnworkedCells Is Nothing Then
            For Each Area In UnworkedCells
                Set GoodCells = AddRanges(GoodCells, SubtractRanges(Area, CommonArea, Not Flip))
            Next Area
        End If

        Set Result = GoodCells
    End If

    Set SubtractRanges = Result
End Function

这里和那里提到的一个小助手函数：

Function AddRanges(RangeA, RangeB)
'
' The same as Union built-in but handles empty ranges fine.
'
    If Not RangeA Is Nothing And Not RangeB Is Nothing Then
        Set AddRanges = Union(RangeA, RangeB)
    ElseIf RangeA Is Nothing And RangeB Is Nothing Then
        Set AddRanges = Nothing
    Else
        If RangeA Is Nothing Then
            Set AddRanges = RangeB
        Else
            Set AddRanges = RangeA
        End If
    End If
End Function

Answer 1

你的分而治之似乎是个好办法。您需要引入一些递归，并且应该相当快。

Private mrBuild As Range

Public Function SubtractRanges(rFirst As Range, rSecond As Range) As Range

    Dim rInter As Range
    Dim rReturn As Range
    Dim rArea As Range

    Set rInter = Intersect(rFirst, rSecond)
    Set mrBuild = Nothing

    If rInter Is Nothing Then 'No overlap
        Set rReturn = rFirst
    ElseIf rInter.Address = rFirst.Address Then 'total overlap
        Set rReturn = Nothing
    Else 'partial overlap
        For Each rArea In rFirst.Areas
            BuildRange rArea, rInter
        Next rArea
        Set rReturn = mrBuild
    End If

    Set SubtractRanges = rReturn

End Function

Sub BuildRange(rArea As Range, rInter As Range)

    Dim rLeft As Range, rRight As Range
    Dim rTop As Range, rBottom As Range

    If Intersect(rArea, rInter) Is Nothing Then 'no overlap
        If mrBuild Is Nothing Then
            Set mrBuild = rArea
        Else
            Set mrBuild = Union(mrBuild, rArea)
        End If
    Else 'some overlap
        If rArea.Columns.Count = 1 Then 'we've exhausted columns, so split on rows
            If rArea.Rows.Count > 1 Then 'if one cell left, don't do anything
                Set rTop = rArea.Resize(rArea.Rows.Count \ 2) 'split the range top to bottom
                Set rBottom = rArea.Resize(rArea.Rows.Count - rTop.Rows.Count).Offset(rTop.Rows.Count)
                BuildRange rTop, rInter 'rerun it
                BuildRange rBottom, rInter
            End If
        Else
            Set rLeft = rArea.Resize(, rArea.Columns.Count \ 2) 'split the range left to right
            Set rRight = rArea.Resize(, rArea.Columns.Count - rLeft.Columns.Count).Offset(, rLeft.Columns.Count)
            BuildRange rLeft, rInter 'rerun it
            BuildRange rRight, rInter
        End If
    End If

End Sub

这些不是特别大的范围，但它们都跑得很快

?subtractranges(rangE("A1"),range("a10")).Address
$A$1
?subtractranges(range("a1"),range("a1")) is nothing
True
?subtractranges(range("$B$3,$B$6,$C$8:$W$39"),range("a1:C10")).Address
$C$11:$C$39,$D$8:$W$39
?subtractranges(range("a1:C10"),range("$B$3,$B$6,$C$8:$W$39")).Address
$A$1:$A$10,$B$1:$B$2,$B$4:$B$5,$B$7:$B$10,$C$1:$C$7

Answer 2

我的解决方案更短，但我不知道它是否是最佳方案：

Sub RangeSubtraction()

    Dim firstRange As Range
    Dim secondRange As Range
    Dim rIntersect As Range
    Dim rOutput As Range
    Dim x As Range

    Set firstRange = Range("A1:B10")
    Set secondRange = Range("A5:B10")

    Set rIntersect = Intersect(firstRange, secondRange)

    For Each x In firstRange
        If Intersect(rIntersect, x) Is Nothing Then
            If rOutput Is Nothing Then 'ugly 'if-else' but needed, can't use Union(Nothing, Range("A1")) etc.
                Set rOutput = x
            Else
                Set rOutput = Application.Union(rOutput, x)
            End If
        End If
    Next x

    Msgbox rOutput.Address

End Sub

Answer 3

虽然迭代而不是递归，但这是我的解决方案。该函数返回由rangeA减去的rangeB

public Function SubtractRange(rangeA Range, rangeB as Range) as Range
'rangeA is a range to subtract from
'rangeB is the range we want to subtract

 Dim existingRange As Range
  Dim resultRange As Range
  Set existingRange = rangeA
  Set resultRange = Nothing
  Dim c As Range
  For Each c In existingRange
  If Intersect(c, rangeB) Is Nothing Then
    If resultRange Is Nothing Then
      Set resultRange = c
    Else
      Set resultRange = Union(c, resultRange)
    End If
  End If
  Next c
  Set SubtractRange = resultRange
End Sub