在VBA中从2D数组中分配1D数组?

时间:2014-03-31 15:49:01

标签: excel-vba multidimensional-array vba excel

所以也许它的星期一,也许我很愚蠢..但我不能为我的生活找到一个很好的方法从2D阵列中的一行获得一维数组。 (也许它不是一个“真正的”2D阵列?)

无论如何,我有一个我这样定义的数组:dim myArr(2,4) as variant

我用值1到15填充它所以看起来像:

1,2,3,4,5
6,7,8,9,10
11,12,13,14,15

所以现在我想要的是该阵列的一行。我能弄明白的唯一方法就是这样做:

    dim temp() as variant
    ReDim temp(lbound(myArr,2) to ubound(myArr,2))

    For i = 0 To 0
        For j = LBound(myArr, 2) To UBound(myArr, 2)
            temp(j) = myArr(i, j)
        Next
    Next

但是我不喜欢这样,因为如果数组变得庞大,那么花费的时间可能要长得多。我认为我应该能够做到:

dim temp as variant
temp = myArr(0) 'since myArr(0) is a 1D array with 5 spots right?

但没有..我得到'错误的维数'错误。

我还通过以前的事情挖回来并发现了这个问题:How to compare two entire rows in a sheet并且蒂姆托马斯的回答显示了转置的使用,并提到你是否比较了你只使用转置一次的列,但它没有工作..如果我这样做:dim myArr(2,0) as variant转置工作,但不是我现在的方式。

我在其他语言(例如C ++和Python)中找到了无数个问题的答案,但我对这两个问题都不熟悉,所以我无法解释它们。

有更好的方法吗? 还是我坚持这个我不喜欢的双循环?

谢谢!

3 个答案:

答案 0 :(得分:11)

这是一个“切片”二维数组的方法的独立插图:

Sub ArraySlicing()

Dim arr(1 To 5, 1 To 5)
Dim slice
Dim x, y
Dim a As Application

    'Populate a sample 2-D array with values...
    For y = 1 To 5
    For x = 1 To 5
        arr(y, x) = "R" & y & ":C" & x
    Next x
    Next y
    '...done setting up sample array

    Set a = Application 'this is just to shorten the following lines

    'Example 1: get the first "column"
    slice = a.Transpose(a.Index(arr, 0, 1))
    Debug.Print Join(slice, ", ") 'display what we got 

    'Example 2: get second "row" (note double transpose)
    slice = a.Transpose(a.Transpose(a.Index(arr, 2, 0)))
    Debug.Print Join(slice, ", ") 'display what we got

End Sub

Index()为你提供了一个二维数组 - (x,1)或(1,x) - Transpose()将它转换为一维数组。

答案 1 :(得分:1)

@dathanm:一个很好的初步方法,但有几点你似乎不清楚:

  1. 在VB中,不需要将布尔值显式地与零进行比较。 VBA解释器自动处理(比较<> 0,实际上,为了测试True条件)。
  2. (@ Tim Williams也是):在你的行切片设计中,调用Transpose方法是不必要的,因为Index返回一行行值的数组,可以按原样使用。按照设计,两个嵌套的Transpose调用本质上是No-Op。有关此问题的完整说明,请参阅我的版本标题注释中的技术说明#3。
  3. Index方法假定基于一个索引,因此您的代码应检查传递的VB数组,该数组不是基于一个(非常常见)并针对该情况进行调整。
  4. 进一步的技术性是,如果调用代码传递了一个锯齿状数组(在VB中并不常见),则Index方法将在列操作上失败,因此您的代码应检查该情况。
  5. 最后,它应该确保返回的切片阵列的基础与切片维度中原始2D阵列的相应基础相同,因为默认情况下不一定是这种情况。涉及索引或转置方法。
  6. 这是我的版本,供任何人根据需要使用:

    Function ArraySlice(Arr2D As Variant, ByCol As Boolean, SliceIdx As Long) As Variant
        '
        'Returns a 1D row or column array "slice" of the specified 2D array.
        '
        'PARAMETERS:
        '
        '   Arr2D       The 2D array from which a row/column slice is to be extracted.  The passed array may be of
        '               any data type.
        '
        '   ByCol       True = slice a column; False = slice a row.
        '
        '   SliceIdx    The array-index of the row or column to be sliced from the 2D array.  Note that the meaning
        '               of SliceIdx value depends on the base of the 2D array's dimensions: a SliceIdx of 1 will be
        '               the first row/column of a one-based array but the second row/column of a zero-based array.
        '
        'RETURN VALUES: If successful, returns a sliced 1D row or column (Variant) array.  If unsuccessful, returns
        '               an Empty Variant status.  Note that, though an array of any data type may be passed to this
        '               routine, the variable receiving the returned array must be a Variant because whole-array
        '               assignment is implemented for Variants only in VB/VBA.
        '
        'TECHNICAL NOTES:
        '
        '   1. IMPORTANT: Though arrays-of-arrays are supported by this routine, jagged arrays-of-arrays (which are
        '      possible in VBA) would be very complex to handle for column-slice operations, so this routine does not
        '      support them for that case and will throw an error message accordingly.  Also, for column-slice
        '      operations on rectangular arrays-of-arrays, this routine assumes that each row-array has the same
        '      LBound (0 or 1 or whatever), which is a condition that can be violated in VB but is extremely unusual.
        '      This routine will throw an error in that case as well.
        '
        '   2. The Application.Index method, used by this routine has two forms, an Array form and a Reference form.
        '      When used by this routine in its Array form, an array (as opposed to a worksheet cell-range reference)
        '      is passed to it and it returns an array as its return value.  In this usage, it doesn't actually
        '      operate on an Excel worksheet range and is therefore very fast, actually faster than any VBA-coded
        '      equivalent algorithm, because its functionality is implemented by Excel's underlying compiled-code
        '      engine.
        '
        '   3. The Index method and the Transpose method are "orientation-aware" with regard to the row/column
        '      orientation of the passed array argument.  For a multi-row and multi-column rectangular array, the
        '      orientation question is moot but for a single-row or single-column array it isn't.  Without those
        '      methods' orientation-awareness, they would require an additional optional parameter that the calling
        '      code would have to set (but only for single-row/column arrays) to inform the methods of the otherwise-
        '      ambiguous orientation of the passed array.  Such a design would further complicate the call interface
        '      as well as the calling code.
        '
        '      Microsoft's solution was to implement the required orientation-awareness by defining single-row arrays
        '      as a simple 1D array containing that row's elements (i.e. RowValues(col-num)), and defining single-
        '      column arrays as a degenerate 2D array containing a single column of each row's value for that column
        '      (i.e. ColValues(row-num, 1)).  That is, those methods determine the orientation of a passed single-
        '      row/column array by simply checking whether it is a 1D array (row) or 2D array (column).  And any
        '      single-row/column array returned by them also conforms to that scheme.  (Technically, it treats the
        '      passed array as an array-of-arrays, regardless of its implementation in VBA, which is consistent with
        '      how simple 2D arrays are implemented in C/C++, the language of Excel's compiled-code engine.)
        '
        '      Consequently, to get a true 1D array of column values, the Index method's returned (degenerate) 2D
        '      array may be passed to the Transpose method, to convert its column-orientation to row-orientation in
        '      the Transpose method's context.  But in the calling-code's context, it becomes just an independent
        '      1D array containing the specified column's values.
        '
        'AUTHOR: Peter Straton
        '
        '*************************************************************************************************************
    
        Const NA As Long = 0
    
        Dim Arr1DSlice As Variant 'NOTE: Some slice operations require a subsequent shift of the sliced array's
                                  'base in order to make it match the corresponding base of the original 2D array,
                                  'in the sliced dimension.  But, because this function's ArraySlice variable is a
                                  'Variant that's also the function's return value, you can't just use Redim Preserve
                                  'to change its base.  Instead, you must us a local (shiftable) Variant and then
                                  'assign that array to the function's return value before returning.
        Dim BaseOffset As Long
        Dim ColIdxLBound As Long
        Dim ColIdxUBound As Long
        Dim i As Long
        Dim IndexFncOffset As Long
        Dim IsArrayOfArrays As Variant  'Variant: can be Empty (undefined) or Boolean
        Dim RowIdxLBound As Long
        Dim RowIdxUBound As Long
    
    
        Arr1DSlice = Empty  'Default: failure status
    
        'First, determine whether Arr2D is a 2D array or array-of-arrays because they are processed differently.
    
        On Error Resume Next
        RowIdxLBound = LBound(Arr2D)
        If Err <> 0 Then Exit Function  'Not an array, so exit with failure status
    
        RowIdxUBound = UBound(Arr2D)
        IsArrayOfArrays = IsArray(Arr2D(RowIdxLBound, RowIdxLBound))
        If IsEmpty(IsArrayOfArrays) Then IsArrayOfArrays = IsArray(Arr2D(RowIdxLBound))
        On Error GoTo 0
    
        'Do the slice operation
    
        With Application
        If ByCol Then
            If IsArrayOfArrays Then
                ColIdxLBound = LBound(Arr2D(RowIdxLBound))  'Assumes consistent column-index LBounds and UBounds for
                ColIdxUBound = UBound(Arr2D(RowIdxLBound))  'each row in the array-of-arrays, but...
    
                'Ensure that it doesn't have inconsistent column-index LBounds and isn't a jagged array-of-arrays
                '(neither of which are supported) by checking each row's column-index bounds.
    
                For i = RowIdxLBound To RowIdxUBound
                    If LBound(Arr2D(i)) <> ColIdxLBound Then
                        MsgBox "Arr1DSlice: Arrays-of-arrays with inconsistent column-index LBounds are not " & _
                               "supported for column operations.", vbOKOnly + vbCritical, "PROGRAMMING ERROR"
                        Exit Function
                    End If
                    If UBound(Arr2D(i)) <> ColIdxUBound Then
                        MsgBox "Arr1DSlice: Jagged arrays-of-arrays are not supported for column operations.", _
                                vbOKOnly + vbCritical, "PROGRAMMING ERROR"
                        Exit Function
                    End If
                Next i
    
            Else 'Standard 2D array
    
                ColIdxLBound = LBound(Arr2D, 2)
                ColIdxUBound = UBound(Arr2D, 2)
            End If
    
            If ColIdxLBound > SliceIdx Then 'If the specified slice-index isn't in-bounds, clip it accordingly
                SliceIdx = ColIdxLBound
            ElseIf ColIdxUBound < SliceIdx Then
                SliceIdx = ColIdxUBound
            End If
    
            IndexFncOffset = 1 - ColIdxLBound 'The Index method assumes one-based indexing, so must adjust for
                                              'non-one-based arrays when that is the case.
    
            Arr1DSlice = .index(Arr2D, NA, SliceIdx + IndexFncOffset) 'Returns a degenerate 2D array of a single
                                                'column's corresponding row values (see TECHNICAL NOTE #3, above),
                                                'so must...
            Arr1DSlice = .Transpose(Arr1DSlice) '...use Transpose to convert it to a 1D array (technically a "row"
                                                'array in the Transpose method's context but is actually just an
                                                'independent 1D array in this context).
    
            'Determine whether the row-dimension base of the original 2D array is different from the base of the
            'resulting sliced array (which is necessarily one-based when generated by the Index method), in order to
            'fix it if necessary, below.  NOTE: the column being sliced from the original 2D array is indexed by its
            'row-position index values, therefore it is the 2D array's row-dimension that must be checked for possible
            'adjustment of the column-sliced 1D array.
    
            BaseOffset = 1 - RowIdxLBound
    
        Else 'ByRow
    
            If RowIdxLBound > SliceIdx Then 'If the specified slice-index isn't in-bounds, clip it accordingly
                SliceIdx = RowIdxLBound
            ElseIf RowIdxUBound < SliceIdx Then
                SliceIdx = RowIdxUBound
            End If
    
            If IsArrayOfArrays Then
    
                Arr1DSlice = Arr2D(SliceIdx) 'For array-of-arrays, just return the SliceIdx row of the 2D array
    
                'NOTE: The Index method is not used here so there is no need to check for an array-base adjustment.
    
            Else 'Standard 2D array
    
                IndexFncOffset = 1 - RowIdxLBound 'The Index method assumes one-based indexing, so must adjust for
                                                  'non-one-based arrays when that is the case.
    
                Arr1DSlice = .index(Arr2D, SliceIdx + IndexFncOffset, NA) 'Slice out the SliceIdx row
    
                'NOTE: in the row-slice case, there is no need to transpose (from column array to row array).
    
                'Determine whether the column-dimension base of the original 2D array is different from the base of
                'the resulting sliced array (which is necessarily one-based when generated by the Index method), in
                'order to fix it if necessary (below).  NOTE: the row being sliced from the original 2D array is
                'indexed by its column-position index values, therefore it is the 2D array's column-dimension that
                'must be checked for possible adjustment of the row-sliced 1D array.
    
                BaseOffset = 1 - LBound(Arr2D, 2)   '(Is never an array-of-arrays here!)
            End If
        End If
    
        If BaseOffset <> 0 Then
            'The base of the original 2D array is different from the base of the resulting sliced array, so fix the
            'sliced array to match the original.
    
            ReDim Preserve Arr1DSlice(LBound(Arr1DSlice) - BaseOffset To UBound(Arr1DSlice) - BaseOffset)
        End If
        End With 'Application
    
        ArraySlice = Arr1DSlice '(See the technical note at the Arr1DSlice variable's declaration)
    End Function
    

    而且,这是一个方便的测试程序,可以用它来玩:

    Sub ArraySliceTest()
        Dim ByCol As Boolean
        Dim ColIdxLBound As Long
        Dim ColIdxUBound As Long
        Dim i As Long
        Dim j As Long
        Dim n As Long
        Dim m As Long
        Dim PadTabs As String
        Dim RowIdxLBound As Long
        Dim RowIdxUBound As Long
        Dim Sliced As Variant
        Dim SliceIdx As Long
        Dim TempBuf1 As Variant
        Dim TempBuf2 As String
        Dim TestArr() As Variant
    
        #Const Std2DArray = True    'For array-of-arrays, set to False
        #Const JaggedArray = False  'For jagged array-of-arrays, set to True
    
    '    ByCol = True    'Uncomment for column slice
        ByCol = False   'Uncomment for row slice
    
    '    SliceIdx = -1  'Uncomment slice-index value to be tested...
    '    SliceIdx = 0
    '    SliceIdx = 1
        SliceIdx = 2
    '    SliceIdx = 3
    '    SliceIdx = 4
    
        #If Std2DArray Then
        '    ReDim TestArr(0 To 2, 0 To 3)  'Uncomment test-array dimensions to be tested...
        '    ReDim TestArr(1 To 3, 1 To 4)
            ReDim TestArr(-1 To 1, -1 To 2)
        '    ReDim TestArr(0 To 2, 1 To 4)
        '    ReDim TestArr(0 To 2, -1 To 2)
        '    ReDim TestArr(1 To 3, 0 To 3)
        '    ReDim TestArr(-1 To 1, 0 To 3)
    
            RowIdxLBound = LBound(TestArr, 1)
            RowIdxUBound = UBound(TestArr, 1)
            ColIdxLBound = LBound(TestArr, 2)
            ColIdxUBound = UBound(TestArr, 2)
    
            'To demonstrate Variant flexibility, use integers for 2D array
    
            For i = RowIdxLBound To RowIdxUBound
                n = n + 1
                m = 0   '(Re)init
                TempBuf1 = vbNullString
                For j = ColIdxLBound To ColIdxUBound
                    m = m + 1
                    TestArr(i, j) = n * 10 + m
                Next j
            Next i
    
        #Else   'For array-of-arrays:
    
            'To demonstrate Variant flexibility, use strings for array-of-arrays
    
            #If Not JaggedArray Then
                TestArr = Array(Array("11", "12", "13", "14"), _
                                Array("21", "22", "23", "24"), _
                                Array("31", "32", "33", "34"))      'Creates an array of arrays.
    
            #Else
                TestArr = Array(Array("11", "12", "13", "14"), _
                                Array("21", "22"), _
                                Array("31", "32", "33", "34"))   'Creates a jagged array of arrays.
    
            #End If
    
            'Test inconsistent col-index LBounds for all rows in an array-of-arrays (unsupported for col slice)
    
    '            Dim X As Variant
    '            #If JaggedArray Then
    '                X = Array("21", "22")
    '            #Else
    '                X = Array("21", "22", "23", "24")
    '            #End If
    '
    '            ReDim Preserve X(LBound(X) - 1 To UBound(X) - 1)
    '            TestArr(2) = X
    
            'Test array-of-arrays col-index LBounds other than the default (supported for row & col slice)
    
    '            Dim X As Variant
    '            Dim Y As Variant
    '            Dim Z As Variant
    '            X = Array("11", "12", "13", "14")
    '            ReDim Preserve X(LBound(X) + 1 To UBound(X) + 1)
    '            Y = Array("21", "22", "23", "24")
    '            ReDim Preserve Y(LBound(Y) + 1 To UBound(Y) + 1)
    '            Z = Array("31", "32", "33", "34")
    '            ReDim Preserve Z(LBound(Z) + 1 To UBound(Z) + 1)
    '            ReDim TestArr(0 To 2)
    '            TestArr(0) = X
    '            TestArr(1) = Y
    '            TestArr(2) = Z
    
            RowIdxLBound = LBound(TestArr)
            RowIdxUBound = UBound(TestArr)
            ColIdxLBound = LBound(TestArr(RowIdxLBound))    'Assumes consistent column-index LBounds and UBounds for
            ColIdxUBound = UBound(TestArr(RowIdxLBound))    'each row in the array-of-arrays (and is used accordingly
                                                            'below).
        #End If 'Std2DArray
    
        'Print the 2D test array
    
        Debug.Print vbLf & "+--- " & IIf(ByCol, "Col", "Row") & " Slice ---+"
        TempBuf1 = vbTab
        TempBuf2 = vbTab
        For j = ColIdxLBound To ColIdxUBound
            TempBuf1 = TempBuf1 & Format(j, IIf(j >= 0, " 0", "#0")) & vbTab
            TempBuf2 = TempBuf2 & ".." & vbTab
        Next j
        Debug.Print Trim$(TempBuf1)
        Debug.Print Trim$(TempBuf2)
    
        For i = RowIdxLBound To RowIdxUBound
            TempBuf1 = vbNullString
            #If Std2DArray Then
                For j = ColIdxLBound To ColIdxUBound
                    TempBuf1 = TempBuf1 & TestArr(i, j) & vbTab
                Next j
            #Else
                For j = LBound(TestArr(i)) To UBound(TestArr(i))    'Handles jagged array-of-arrays
                    TempBuf1 = TempBuf1 & TestArr(i)(j) & vbTab
                Next j
            #End If
            Debug.Print Format(i, IIf(i >= 0, " 0", "#0")) & ":" & vbTab & Trim$(TempBuf1)
        Next i
    
        'Get the slice
    
        Sliced = ArraySlice(Arr2D:=TestArr, ByCol:=ByCol, SliceIdx:=SliceIdx)
    
        If Not IsEmpty(Sliced) Then
            'Succeeded, so print the 1D slice array
    
            PadTabs = String(SliceIdx - LBound(Sliced), vbTab)
            Debug.Print
            If ByCol Then
    '            Debug.Print vbTab & PadTabs & Format(SliceIdx, IIf(SliceIdx >= 0, " 0", "#0"))
    '            Debug.Print vbTab & PadTabs & ".."
    
                For i = LBound(Sliced) To UBound(Sliced)
                    Debug.Print Format(i, IIf(i >= 0, " 0", "#0")) & ": " & PadTabs & Sliced(i)
                Next i
            Else
                TempBuf1 = Format(SliceIdx, IIf(SliceIdx >= 0, " 0", "#0")) & ":" & vbTab
                For i = LBound(Sliced) To UBound(Sliced)
                    TempBuf1 = TempBuf1 & Sliced(i) & vbTab
                Next i
    
                Debug.Print TempBuf1
            End If
        Else
            MsgBox "The ArraySlice function call failed"
        End If
    
        Debug.Print "+-----------------+"
    End Sub
    

答案 2 :(得分:-1)

    Public Function VectorizeArrayCols(Arr As Variant) As Variant
        Dim n, nn, n3, k As Long

        n = UBound(Arr, 1)
        nn = UBound(Arr, 2)
        'n = Arr.Columns.Count       'if Public Function Vectorize(Arr As Range) As String
        'nn = Arr.Rows.Count         'if Public Function Vectorize(Arr As Range) As String
        n3 = n * nn

        Dim Vx() As Variant
        ReDim Vx(n3)

        For i = 1 To n
            For j = 1 To nn
                k = i + n * (j - 1)
                Vx(k) = Arr(i, j)
            Next j
        Next i

        VectorizeArrayCols = Vx

    End Function