Question

我需要获得所有可能组合的列表，而不是排列。

为了确保我有正确的名字，对我来说123和321是相同的，只应列出一次。

下面的代码可以满足我的需要，但我无法将其转换为MS Access vba。

对不起，我知道这是基本的，已被问过一百万次，但我找不到任何适用于我的MS Access。

 Sub test_print_nCr()
      print_nCr 7, 3, Range("A1")
    End Sub

2

Public Function print_nCr(n As Integer, r As Integer, p As Range)

  c = 1
  internal_print_nCr n, r, p, 1, 1
End Function

3

Public Function internal_print_nCr(n As Integer, r As Integer, ByVal p As Range, Optional i As Integer, Optional l As Integer) As Integer

  ' n is the number of items we are choosing from
  ' r is the number of items to choose
  ' p is the upper corner of the output range
  ' i is the minimum item we are allowed to pick
  ' l is how many levels we are in to the choosing
  ' c is the complete set we are working on

  If n < 1 Or r > n Or r < 0 Then Err.Raise 1
  If i < 1 Then i = 1
  If l < 1 Then l = 1
  If c < 1 Then c = 1
  If r = 0 Then
    p = 1
    Exit Function
  End If

  Dim x As Integer
  Dim y As Integer

  For x = i To n - r + 1
    If r = 1 Then
      If c > 1 Then
        For y = 0 To l - 2
          If p.Offset(c - 1, y) = "" Then p.Offset(c - 1, y) = p.Offset(c - 2, y)
        Next
      End If
      p.Offset(c - 1, l - 1) = x
      c = c + 1
    Else
      p.Offset(c - 1, l - 1) = x
      internal_print_nCr n, r - 1, p, x + 1, l + 1
    End If
  Next

End Function

再次感谢你

Answer 1

我不确定这是否是执行此操作的最佳方法，但我会使用一种二进制表示法。例如，考虑字母数n = 3的单词“boy”。这个单词有三个字母，所以你可以使用这样的东西：

001 = y， 010 = o， 011 = oy， 100 = b， 101 = by， 110 =博， 111 =男孩。

左侧可以用从i = 1到幂（2，n）-1的循环完成，并将i转换为二进制基数。因此，您唯一需要做的就是使用非null位置来构建组合。

可能在Knuth中有一些比这更有趣的东西。

Answer 2

我在这里找到了这个代码，它给了我我需要的东西。你只需要创建一个1-100的数字表。以下链接中的说明

enter link description here

谢谢大家

Public Sub buildquery(strN As String, K As Integer)
    Dim qd As DAO.QueryDef
    Dim intI As Integer
    Dim strsql As String
    Dim strSelect As String
    Dim strFrom As String
    Dim strWhere As String

    Set qd = CurrentDb.QueryDefs("QN")
    qd.sql = "SELECT N FROM tblN WHERE N IN (" & strN & ")"
    Set qd = Nothing
    strSelect = "SELECT QN.N "
    strFrom = "FROM QN "
    strWhere = "WHERE QN_1.N > QN.N "
    For intI = 1 To K - 1
        strSelect = strSelect & ", QN_" & intI & ".N AS N" & intI & " "
        strFrom = strFrom & ", QN AS QN_" & intI & " "
        If intI < K - 1 Then
            strWhere = strWhere & " AND QN_" & intI + 1 & ".N > QN_" & intI & ".N "
        End If
    Next
    strsql = strSelect & " INTO tblCombinations " & strFrom & strWhere
    DoCmd.SetWarnings False
    DoCmd.RunSQL strsql
    DoCmd.SetWarnings True
End Sub

然后测试

Public Sub testbuildquery()
  buildquery "1,2,3,4,5,6,7", 3
End Sub

所有可能的组合

2 个答案: