Sort keys in dictionary

Question

I have a set of numeric keys I want sorted from smallest to largest.

Dim result
Set result = CreateObject("Scripting.Dictionary")

For i = 1 To N
    weeksThisIteration = 0

    Do While conditiaonTrue
        //...
        weeksThisIteration = weeksThisIteration + 1
    Loop

    'If Not result.Item(weeksThisIteration) Then
    '    result.Add weeksThisIteration, 0//apparently I don't have to initiailize
    'End If

    result.Item(weeksThisIteration) = result.Item(weeksThisIteration) + 1

I want to sort result, preferably within a sub/function. I tried:

• Creating a sub MySort(list As Scripting.Dictionary)

I had problems passing the value. I added a reference to "Microsoft Scripting Runtime". I still got an error about passing ByRef when I called the method, plus I'm unsure of the implementation.

• Calling a native function SortDictionary. VBA said the func doesn't exist.

How can I implement a numeric KEY sort in a method and call it with this data type?

Answer 1

John Bustos answer is a good one. The sort makes an undocumented assumption that your dictionary.keys are all strings. In my case the keys are integers. I made the conversion change in the Load portion of SortDictionary:

   ' Load TempDict. The key value come from
    ' our sorted array of keys Arr, and the
    ' Item comes from the original Dict object.
    ''''''''''''''''''''''''''''''''''''''''''''
    For Ndx = 0 To Dict.Count - 1
        KeyValue = Arr(Ndx)
        'MsgBox "key: " & KeyValue & "Item Value: " & Dict.Item(CInt(KeyValue))
        TempDict.Add Key:=KeyValue, Item:=Dict.Item(CInt(KeyValue))'Convert here
    Next Ndx

Also you need QSortInPlace to make this code work. Linking on jsfiddle in case the author's link dies one day. The code is too long to post directly into SO.

Answer 2

Have a look at this page.

Specifically, he has a section called SortDictionary:

Public Sub SortDictionary(Dict As Scripting.Dictionary, _
    SortByKey As Boolean, _
    Optional Descending As Boolean = False, _
    Optional CompareMode As VbCompareMethod = vbTextCompare)
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
' SortDictionary
' This sorts a Dictionary object. If SortByKey is False, the
' the sort is done based on the Items of the Dictionary, and
' these items must be simple data types. They may not be
' Object, Arrays, or User-Defined Types. If SortByKey is True,
' the Dictionary is sorted by Key value, and the Items in the
' Dictionary may be Object as well as simple variables.
'
' If sort by key is True, all element of the Dictionary
' must have a non-blank Key value. If Key is vbNullString
' the procedure will terminate.
'
' By defualt, sorting is done in Ascending order. You can
' sort by Descending order by setting the Descending parameter
' to True.
'
' By default, text comparisons are done case-INSENSITIVE (e.g.,
' "a" = "A"). To use case-SENSITIVE comparisons (e.g., "a" <> "A")
' set CompareMode to vbBinaryCompare.
'
' Note: This procedure requires the
' QSortInPlace function, which is described and available for
' download at www.cpearson.com/excel/qsort.htm .
'
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''

Dim Ndx As Long
Dim KeyValue As String
Dim ItemValue As Variant
Dim Arr() As Variant
Dim KeyArr() As String
Dim VTypes() As VbVarType


Dim V As Variant
Dim SplitArr As Variant

Dim TempDict As Scripting.Dictionary
'''''''''''''''''''''''''''''
' Ensure Dict is not Nothing.
'''''''''''''''''''''''''''''
If Dict Is Nothing Then
    Exit Sub
End If
''''''''''''''''''''''''''''
' If the number of elements
' in Dict is 0 or 1, no
' sorting is required.
''''''''''''''''''''''''''''
If (Dict.Count = 0) Or (Dict.Count = 1) Then
    Exit Sub
End If

''''''''''''''''''''''''''''
' Create a new TempDict.
''''''''''''''''''''''''''''
Set TempDict = New Scripting.Dictionary

If SortByKey = True Then
    ''''''''''''''''''''''''''''''''''''''''
    ' We're sorting by key. Redim the Arr
    ' to the number of elements in the
    ' Dict object, and load that array
    ' with the key names.
    ''''''''''''''''''''''''''''''''''''''''
    ReDim Arr(0 To Dict.Count - 1)

    For Ndx = 0 To Dict.Count - 1
        Arr(Ndx) = Dict.Keys(Ndx)
    Next Ndx

    ''''''''''''''''''''''''''''''''''''''
    ' Sort the key names.
    ''''''''''''''''''''''''''''''''''''''
    QSortInPlace InputArray:=Arr, LB:=-1, UB:=-1, Descending:=Descending, CompareMode:=CompareMode
    ''''''''''''''''''''''''''''''''''''''''''''
    ' Load TempDict. The key value come from
    ' our sorted array of keys Arr, and the
    ' Item comes from the original Dict object.
    ''''''''''''''''''''''''''''''''''''''''''''
    For Ndx = 0 To Dict.Count - 1
        KeyValue = Arr(Ndx)
        TempDict.Add Key:=KeyValue, Item:=Dict.Item(KeyValue)
    Next Ndx
    '''''''''''''''''''''''''''''''''
    ' Set the passed in Dict object
    ' to our TempDict object.
    '''''''''''''''''''''''''''''''''
    Set Dict = TempDict
    ''''''''''''''''''''''''''''''''
    ' This is the end of processing.
    ''''''''''''''''''''''''''''''''
Else
    '''''''''''''''''''''''''''''''''''''''''''''''
    ' Here, we're sorting by items. The Items must
    ' be simple data types. They may NOT be Objects,
    ' arrays, or UserDefineTypes.
    ' First, ReDim Arr and VTypes to the number
    ' of elements in the Dict object. Arr will
    ' hold a string containing
    '   Item & vbNullChar & Key
    ' This keeps the association between the
    ' item and its key.
    '''''''''''''''''''''''''''''''''''''''''''''''
    ReDim Arr(0 To Dict.Count - 1)
    ReDim VTypes(0 To Dict.Count - 1)

    For Ndx = 0 To Dict.Count - 1
        If (IsObject(Dict.Items(Ndx)) = True) Or _
            (IsArray(Dict.Items(Ndx)) = True) Or _
            VarType(Dict.Items(Ndx)) = vbUserDefinedType Then
            Debug.Print "***** ITEM IN DICTIONARY WAS OBJECT OR ARRAY OR UDT"
            Exit Sub
        End If
        ''''''''''''''''''''''''''''''''''''''''''''''''''''''''
        ' Here, we create a string containing
        '       Item & vbNullChar & Key
        ' This preserves the associate between an item and its
        ' key. Store the VarType of the Item in the VTypes
        ' array. We'll use these values later to convert
        ' back to the proper data type for Item.
        ''''''''''''''''''''''''''''''''''''''''''''''''''''''''
            Arr(Ndx) = Dict.Items(Ndx) & vbNullChar & Dict.Keys(Ndx)
            VTypes(Ndx) = VarType(Dict.Items(Ndx))

    Next Ndx
    ''''''''''''''''''''''''''''''''''
    ' Sort the array that contains the
    ' items of the Dictionary along
    ' with their associated keys
    ''''''''''''''''''''''''''''''''''
    QSortInPlace InputArray:=Arr, LB:=-1, UB:=-1, Descending:=Descending, CompareMode:=vbTextCompare

    For Ndx = LBound(Arr) To UBound(Arr)
        '''''''''''''''''''''''''''''''''''''
        ' Loop trhogh the array of sorted
        ' Items, Split based on vbNullChar
        ' to get the Key from the element
        ' of the array Arr.
        SplitArr = Split(Arr(Ndx), vbNullChar)
        ''''''''''''''''''''''''''''''''''''''''''
        ' It may have been possible that item in
        ' the dictionary contains a vbNullChar.
        ' Therefore, use UBound to get the
        ' key value, which will necessarily
        ' be the last item of SplitArr.
        ' Then Redim Preserve SplitArr
        ' to UBound - 1 to get rid of the
        ' Key element, and use Join
        ' to reassemble to original value
        ' of the Item.
        '''''''''''''''''''''''''''''''''''''''''
        KeyValue = SplitArr(UBound(SplitArr))
        ReDim Preserve SplitArr(LBound(SplitArr) To UBound(SplitArr) - 1)
        ItemValue = Join(SplitArr, vbNullChar)
        '''''''''''''''''''''''''''''''''''''''
        ' Join will set ItemValue to a string
        ' regardless of what the original
        ' data type was. Test the VTypes(Ndx)
        ' value to convert ItemValue back to
        ' the proper data type.
        '''''''''''''''''''''''''''''''''''''''
        Select Case VTypes(Ndx)
            Case vbBoolean
                ItemValue = CBool(ItemValue)
            Case vbByte
                ItemValue = CByte(ItemValue)
            Case vbCurrency
                ItemValue = CCur(ItemValue)
            Case vbDate
                ItemValue = CDate(ItemValue)
            Case vbDecimal
                ItemValue = CDec(ItemValue)
            Case vbDouble
                ItemValue = CDbl(ItemValue)
            Case vbInteger
                ItemValue = CInt(ItemValue)
            Case vbLong
                ItemValue = CLng(ItemValue)
            Case vbSingle
                ItemValue = CSng(ItemValue)
            Case vbString
                ItemValue = CStr(ItemValue)
            Case Else
                ItemValue = ItemValue
        End Select
        ''''''''''''''''''''''''''''''''''''''
        ' Finally, add the Item and Key to
        ' our TempDict dictionary.

        TempDict.Add Key:=KeyValue, Item:=ItemValue
    Next Ndx
End If


'''''''''''''''''''''''''''''''''
' Set the passed in Dict object
' to our TempDict object.
'''''''''''''''''''''''''''''''''
Set Dict = TempDict
End Sub