VBA中的减法范围（Excel）

SIO 发表于 Dev

SIO

我想做什么

我正在尝试编写一个函数来减去Excel范围。它应该接受两个输入参数：范围A和范围B。它应该返回范围对象，该对象由范围A的一部分而不是范围B的单元组成（如在集减法中一样）

我尝试过的

我在网上看到了一些使用临时工作表执行此操作的示例（快速，但可能会引入受保护的工作簿等问题），还有一些其他示例，它们逐个单元格地检查第一个范围是否与第二个范围相交一（极其慢）。

经过一番思考，我想出了这段代码{1}，它可以运行得更快，但是仍然很慢。从代表整个工作表的范围中减去需要1到5分钟，具体取决于第二个范围的复杂程度。

当我查看该代码以尝试找到使其更快时的方法时，我发现可以应用分而治之范式了，我做了{2}。但这使我的代码变慢了。我不是CS专家，所以我可能做错了什么，或者我不知道此算法根本不是应该使用分治法的算法。

我也尝试过主要使用递归来重写它，但是这花了很长时间才能完成，或者（更经常地）抛出了Out of Stack Space错误。我没有保存代码。

我能够做的唯一（略微）成功的改进是添加一个翻转开关{3}并先通过行，然后（在下一个调用中）通过列，而不是在同一个调用中都通过，但是效果不如我所希望的那样。现在我看到，即使我们没有遍历第一次调用中的所有行，但在第二次调用中，我们仍然循环遍历与第一次调用中相同的行数，只是这些行稍短一些：）

感谢您在改进或重写此功能方面的帮助，谢谢！

该解决方案基于Dick Kusleika接受的答案

Dick Kusleika，非常感谢您提供答案！我想我将在进行一些修改后使用它：

摆脱了全局变量（mrBuild）
修复了“某些重叠”条件，以排除“无重叠”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拆分范围

通过这些修改，代码可以在大多数常见情况下非常快速地运行。正如已经指出的那样，棋盘风格的巨大范围仍然会很慢，我同意这是不可避免的。

我认为这段代码仍有改进的余地，如果我对其进行修改，我将对其进行更新。

改进的可能性：

选择如何分割范围（按列或按行）的试探法

{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}分而治之

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

此处提到的一些辅助功能：

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

迪克·库斯莱卡（Dick Kusleika）

您的分而治之似乎是一个好方法。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

这些范围不是特别大，但是它们都运行很快

?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

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编辑于2021-02-6

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