VBA中的哈希表/关联数组

Question

我似乎无法找到解释如何在VBA中创建哈希表或关联数组的文档.它甚至可能吗？

你可以链接到一篇文章或更好地发布代码吗？

Answer 1

我想你正在寻找在Microsoft Scripting Runtime库中找到的Dictionary对象.(从VBE的Tools ... References菜单中添加对项目的引用.)

它几乎适用于任何适合变体的简单值(键不能是数组,并且尝试使它们成为对象没有多大意义.请参阅下面的@Nile中的注释.):

Dim d As dictionary
Set d = New dictionary

d("x") = 42
d(42) = "forty-two"
d(CVErr(xlErrValue)) = "Excel #VALUE!"
Set d(101) = New Collection

如果您的需求更简单并且您只需要字符串键,也可以使用VBA Collection对象.

我不知道是否实际上有任何哈希值,所以如果你需要类似哈希表的性能,你可能想要进一步挖掘.(编辑:Scripting.Dictionary在内部使用哈希表.)

Answer 2

我曾经多次使用过Francesco Balena的HashTable类,当时Collection或Dictionary不是完美的,我只需要一个HashTable.

Answer 3

尝试使用Dictionary对象或Collection对象.

http://visualbasic.ittoolbox.com/documents/dictionary-object-vs-collection-object-12196

Answer 4

在这里,我们去...只需将代码复制到模块,它就可以使用了

Private Type hashtable
    key As Variant
    value As Variant
End Type

Private GetErrMsg As String

Private Function CreateHashTable(htable() As hashtable) As Boolean
    GetErrMsg = ""
    On Error GoTo CreateErr
        ReDim htable(0)
        CreateHashTable = True
    Exit Function

CreateErr:
    CreateHashTable = False
    GetErrMsg = Err.Description
End Function

Private Function AddValue(htable() As hashtable, key As Variant, value As Variant) As Long
    GetErrMsg = ""
    On Error GoTo AddErr
        Dim idx As Long
        idx = UBound(htable) + 1

        Dim htVal As hashtable
        htVal.key = key
        htVal.value = value

        Dim i As Long
        For i = 1 To UBound(htable)
            If htable(i).key = key Then Err.Raise 9999, , "Key [" & CStr(key) & "] is not unique"
        Next i

        ReDim Preserve htable(idx)

        htable(idx) = htVal
        AddValue = idx
    Exit Function

AddErr:
    AddValue = 0
    GetErrMsg = Err.Description
End Function

Private Function RemoveValue(htable() As hashtable, key As Variant) As Boolean
    GetErrMsg = ""
    On Error GoTo RemoveErr

        Dim i As Long, idx As Long
        Dim htTemp() As hashtable
        idx = 0

        For i = 1 To UBound(htable)
            If htable(i).key <> key And IsEmpty(htable(i).key) = False Then
                ReDim Preserve htTemp(idx)
                AddValue htTemp, htable(i).key, htable(i).value
                idx = idx + 1
            End If
        Next i

        If UBound(htable) = UBound(htTemp) Then Err.Raise 9998, , "Key [" & CStr(key) & "] not found"

        htable = htTemp
        RemoveValue = True
    Exit Function

RemoveErr:
    RemoveValue = False
    GetErrMsg = Err.Description
End Function

Private Function GetValue(htable() As hashtable, key As Variant) As Variant
    GetErrMsg = ""
    On Error GoTo GetValueErr
        Dim found As Boolean
        found = False

        For i = 1 To UBound(htable)
            If htable(i).key = key And IsEmpty(htable(i).key) = False Then
                GetValue = htable(i).value
                Exit Function
            End If
        Next i
        Err.Raise 9997, , "Key [" & CStr(key) & "] not found"

    Exit Function

GetValueErr:
    GetValue = ""
    GetErrMsg = Err.Description
End Function

Private Function GetValueCount(htable() As hashtable) As Long
    GetErrMsg = ""
    On Error GoTo GetValueCountErr
        GetValueCount = UBound(htable)
    Exit Function

GetValueCountErr:
    GetValueCount = 0
    GetErrMsg = Err.Description
End Function

要在VB(A)App中使用:

Public Sub Test()
    Dim hashtbl() As hashtable
    Debug.Print "Create Hashtable: " & CreateHashTable(hashtbl)
    Debug.Print ""
    Debug.Print "ID Test   Add V1: " & AddValue(hashtbl, "Hallo_0", "Testwert 0")
    Debug.Print "ID Test   Add V2: " & AddValue(hashtbl, "Hallo_0", "Testwert 0")
    Debug.Print "ID Test 1 Add V1: " & AddValue(hashtbl, "Hallo.1", "Testwert 1")
    Debug.Print "ID Test 2 Add V1: " & AddValue(hashtbl, "Hallo-2", "Testwert 2")
    Debug.Print "ID Test 3 Add V1: " & AddValue(hashtbl, "Hallo 3", "Testwert 3")
    Debug.Print ""
    Debug.Print "Test 1 Removed V1: " & RemoveValue(hashtbl, "Hallo_1")
    Debug.Print "Test 1 Removed V2: " & RemoveValue(hashtbl, "Hallo_1")
    Debug.Print "Test 2 Removed V1: " & RemoveValue(hashtbl, "Hallo-2")
    Debug.Print ""
    Debug.Print "Value Test 3: " & CStr(GetValue(hashtbl, "Hallo 3"))
    Debug.Print "Value Test 1: " & CStr(GetValue(hashtbl, "Hallo_1"))
    Debug.Print ""
    Debug.Print "Hashtable Content:"

    For i = 1 To UBound(hashtbl)
        Debug.Print CStr(i) & ": " & CStr(hashtbl(i).key) & " - " & CStr(hashtbl(i).value)
    Next i

    Debug.Print ""
    Debug.Print "Count: " & CStr(GetValueCount(hashtbl))
End Sub