Excel VBA - count the duplicates

Question

I have two arrays which contains string values in them. Let us consider the example as below.

• Array 1: Computer science, Artificial Intelligence
• Array 2: Eclipse, MS, RAD, Linux, Artificial Intelligence

I need to find the number of duplicates in both of my arrays. In the above case, I need the total duplicate value as 1 (since Artificial Intelligence is in both Array1 and Array2). Is there a way to do this in VBA?

Answer 1

This function assumes that arr2 is a 1-dimensional array:

Function ArrDupCount(ByVal arr1 As Variant, ByVal arr2 As Variant) As Long

    Dim varElement As Variant
    Dim lMatch As Long

    On Error Resume Next
    For Each varElement In arr1
        lMatch = 0
        lMatch = WorksheetFunction.Match(varElement, arr2, 0)
        If lMatch > 0 Then ArrDupCount = ArrDupCount + 1
    Next varElement
    On Error GoTo 0

End Function

To use it:

Sub tgr()

    Dim arr1 As Variant
    Dim arr2 As Variant

    arr1 = Array("Computer science", "Artificial Intelligence")
    arr2 = Array("Eclipse", "MS", "RAD", "Linux", "Artificial Intelligence")

    MsgBox ArrDupCount(arr1, arr2)  ' => 1

End Sub