Pass dictionary keys into stack object vba

Hi Guys,

I have a code:

Sub test()
    Dim cs As Object
    Set cs = CreateObject("System.Collections.Stack")
    Dim dic As Object
    Set dic = CreateObject("Scripting.dictionary")
    Dim i As Long
    
    dic.Add "ok", 1
    dic.Add "ok2", 2
    dic.Add "ok3", 3

    With cs

             Debug.Print CStr(.Push(dic.keys))
''

        For i = 1 To 10
            Debug.Print CStr(.Pop)
        Next i
        
    End With
End Sub

Here i have stack object and dictionary object.

I am passing whole dictionary into first stack item like here:
stack item.png

And now i would like to retrieve second dictionary key from first item in stack so in this case it will be item 1(1) - "ok2".

How can i do it ?

I tried to implement methods like

"Debug.Print CStr(.Pop)(1)(1) but there is an error.

Please help,
Jacek Antek

Hi Kyle,

thank you for your help and support,

aa you are right, here i am passing dictionary:

stack item.png

the purpose of using stack object is to get the list of values from dictionary in descending order.

Can I ask you what error do you have ? It is strange...
Here is more about stack object in VBA:

http://analystcave.com/excel-vba-dic...ta-structures/

Best wishes,
Jacek

I understand what a stack is. My Excel hard crashes, I suspect it maybe down to me using 64-bit Excel.

I fear you may have misunderstood the point of a stack, or indeed what it's for. It will return the order of which things are added to it (in reverse) - it's not for ascending or descending anything (sorting).

To get values from the dictionary in descending order, you will need to sort the keys. You could do this with a sort mechanism, or you could use something like an arraylist that has a sort built in.

Additionally, I don't understand the relevance of your screenshot - the stack is empty.

Try

    With cs
             Debug.Print CStr(.Push(dic.keys))
             MsgBox .ToArray()(0)(1)

You realise that dictionaries don't guarantee order right? That's why you can't loop through them - that's why you can only access by key.

If you need to guarantee order, you need to use another data structure, a collection or array for example.

No, but I wouldn't rely on it

TBH I'm not convinced that it ever will, I've certainly never encountered it. The issue is that you can overwrite values in a dictionary, you can't with a collection.

This means that the order of values can change in a dictionary, it can't in a collection unless explicitly inserted/removed - they'll always be in which the order they added.

Thank you Kyle123,

yes maybe you have right but i am using the same thing (dictianary + array bubble sorting) in Excel and never users have had any problems connected with this.
In dictionary items are added one by one and there is no chance to change the order.

Thank you,
Best wishes,
Jacek

Debug.Print CStr(.Peek().keys()(i - 1))

xlnitwit could you please explain what keys method is doing here?

It is peek method yes ?

Sorry i have to understand it.

Best wishes,
Jacek

Up

Jacek Antek

thank you xlnitwit !

Best Wishes and have a nice day,
Jacek

I suspect that something like the following is more efficient:

Function returnDicElements(ByRef dic As Object, Optional FILO As Boolean = True) As Variant
    
    Dim start As Long, finish As Long, x As Long
    Dim keys As Variant, out() As Variant
    
    keys = dic.keys()
    
    ReDim out(0 To UBound(keys))
    
    start = LBound(keys)
    finish = UBound(keys)

    For x = start To finish
       If FILO Then
        out(x) = dic(keys(finish - x))
       Else
        out(x) = dic(keys(x))
       End If
    Next x
    
    returnDicElements = out
    
End Function