Create reference table or array inside of the code - arrays

Question

I am trying to create a function that allows me to put in a location number and the result will give me a unique location code. The problem is I want all of the referencing done inside of the macro code, not to get the information from somewhere in the spreadsheet. (this code is going into an add-in so there is no worksheet to reference from). I basically want to do a vlookup but inside of the code, not in a worksheet.
I haven't been able to find out how to do this, the code below is something like what I am looking for, I am thinking maybe the use of an array but I can't figure out how to use it the way I want.
I know this doesn't work but I am trying to do something like this below so that when I type in =GetCode(415) the result is 001
Function GetCode(LocationNum As String) As String
Dim Result As String
'Built in reference table
'
'{ "415" : "001"
' "500" : "002"
' "605" : "003"
' }
Dim varData(2) As Variant
varData("415") = "001"
varData("500") = "002"
varData("605") = "003"
Result = varData(LocationNum)
GetCode = Result
End Function

Answer 1

As Nathan_Sav has already mentioned, you can use a collection or dictionary instead, which are much more efficient. Here's an example using the dictionary object. Note that it uses early binding, so you'll need to set a reference to the Microsoft Scripting Runtime library (Visual Basic Editor >> Tools >> Reference).
Option Explicit
Sub test()
'set a reference (VBE >> Tools >> Reference) to the Microsoft Scripting Runtime library
'declare and create an instance of the dictionary object
Dim dic As Scripting.Dictionary
Set dic = New Scripting.Dictionary
'set the comparison mode for the dictionary to a case-insensitive match
dic.CompareMode = TextCompare
'add keys and associated items to the dictionary
dic.Add Key:="415", Item:="001"
dic.Add Key:="500", Item:="002"
dic.Add Key:="605", Item:="003"
'print to the immediate window the item associated with the specified key
Debug.Print dic("415")
'clear from memory
Set dic = Nothing
End Sub