Do I need an array, class, dictionary, or collection? - excel

Question

I am not sure what the best option is for what I'm trying to do. Currently, I'm using a 3D array to hold these values, but I am just now learning about dictionaries, classes, and collections in VBA and can't determine if any of those would be better or more useful for what I'm trying to do.
I get a new spreadsheet of data every month, and I need to loop through cells looking for a number, and replace another cell's data based on that number. I.E. (all in Col. A)
4323
4233
4123
4343
4356
3213
In column B, I need to put a corresponding country. If the first two digits are 43, the cell to the right should be "Germany" and then in col. C, "DEU". If the two numbers are 41, then the col. B cell should be "USA", and in C, "USA"...etc. etc.
Currently, I'm setting up a 3D array (psuedo code):
myArray(0,0) = 43
myArray(0,1) = "Germany"
myArray(0,2) = "DEU"
myArray(1,0) = 41
myArray(1,1) = "United States"
myArray(1,2) = "USA"
etc. etc.
Then, I have a loop going through all the cells and replacing the information.
Would a class perhaps be better? I could then do something like create a cntry. Code, cntry.Country, cntry.CountryAbbrev and use those to refer to "43", "Germany", and "DEU"
(again, psuedo code):
num = left("A1",2)
'then here, somehow find the num in cntry.Code list - will need to work out how
Cells("B1").Value = cntry.Country
Cells("C1").Value = cntry.CountryAbbrev
...
As for Dictionaries, I think that won't work, as (AFAIK) you can only have one key per entry. So I could do the country number ("43") but set only either the Country name or Country Abbreviation - but not both....correct?
Does this question make sense? Is using a class/dictionary overkill on something like this? Would a collection be best?
Thanks for any advice/guidance!

Answer 1

Class Module is the answer. It's always the answer. Code is code and there's almost nothing you can do in a class module that you can't do in a standard module. Classes are just a way to organize your code differently.
But the next question becomes how to store your data inside your class module. I use Collections out of habit, but Collection or Scripting.Dictionary are your best choices.
I'd make a class called CCountry that looks like this
Private mlCountryID As Long
Private msCode As String
Private msFullname As String
Private msAbbreviation As String
Public Property Let CountryID(ByVal lCountryID As Long): mlCountryID = lCountryID: End Property
Public Property Get CountryID() As Long: CountryID = mlCountryID: End Property
Public Property Let Code(ByVal sCode As String): msCode = sCode: End Property
Public Property Get Code() As String: Code = msCode: End Property
Public Property Let Fullname(ByVal sFullname As String): msFullname = sFullname: End Property
Public Property Get Fullname() As String: Fullname = msFullname: End Property
Public Property Let Abbreviation(ByVal sAbbreviation As String): msAbbreviation = sAbbreviation: End Property
Public Property Get Abbreviation() As String: Abbreviation = msAbbreviation: End Property
Then I'd make a class called CCountries to hold all of my CCountry instances
Private mcolCountries As Collection
Private Sub Class_Initialize()
Set mcolCountries = New Collection
End Sub
Private Sub Class_Terminate()
Set mcolCountries = Nothing
End Sub
Public Property Get NewEnum() As IUnknown
Set NewEnum = mcolCountries.[_NewEnum]
End Property
Public Sub Add(clsCountry As CCountry)
If clsCountry.CountryID = 0 Then
clsCountry.CountryID = Me.Count + 1
End If
mcolCountries.Add clsCountry, CStr(clsCountry.CountryID)
End Sub
Public Property Get Country(vItem As Variant) As CCountry
Set Country = mcolCountries.Item(vItem)
End Property
Public Property Get Count() As Long
Count = mcolCountries.Count
End Property
You see that CCountries is merely a Collection at this point. You can read more about that NewEnum property at http://dailydoseofexcel.com/archives/2010/07/09/creating-a-parent-class/
Then I'd put all my country stuff in a Table and read that table into my class. In CCountries
Public Sub FillFromRange(rRng As Range)
Dim vaValues As Variant
Dim i As Long
Dim clsCountry As CCountry
vaValues = rRng.Value
For i = LBound(vaValues, 1) To UBound(vaValues, 1)
Set clsCountry = New CCountry
With clsCountry
.Code = vaValues(i, 1)
.Fullname = vaValues(i, 2)
.Abbreviation = vaValues(i, 3)
End With
Me.Add clsCountry
Next i
End Sub
I'd need a way to find a country by one of its properties
Public Property Get CountryBy(ByVal sProperty As String, ByVal vValue As Variant) As CCountry
Dim clsReturn As CCountry
Dim clsCountry As CCountry
For Each clsCountry In Me
If CallByName(clsCountry, sProperty, VbGet) = vValue Then
Set clsReturn = clsCountry
Exit For
End If
Next clsCountry
Set CountryBy = clsReturn
End Property
Then I'd run down my list of numbers and put the codes next to them
Sub FillCodes()
Dim clsCountries As CCountries
Dim rCell As Range
Dim clsCountry As CCountry
Set clsCountries = New CCountries
clsCountries.FillFromRange Sheet1.ListObjects("tblCountries").DataBodyRange
For Each rCell In Sheet2.Range("A3:A5").Cells
Set clsCountry = Nothing
Set clsCountry = clsCountries.CountryBy("Code", CStr(rCell.Value))
If Not clsCountry Is Nothing Then
rCell.Offset(0, 1).Value = clsCountry.Fullname
rCell.Offset(0, 2).Value = clsCountry.Abbreviation
End If
Next rCell
End Sub
Other than defining where the codes I'm looping through are, I don't really need any comments. You can tell what's going on my the name of the object and the properties or methods. That's the payoff for the extra work in setting up class modules - IMO.

Answer 2

You can have a dictionary of objects or dictionaries.
VBA has several methods to store data:
a Dictionary
a Collection
an array (matrix) variable
an ActiveX ComboBox
an ActiveX ListBox
a Userform control ComboBox
a Userform control ListBox
a sortedlist
an arraylist
I suggest you to read the following article:
http://www.snb-vba.eu/VBA_Dictionary_en.html