In VBA, how to check if two arrays contain the same element? - vba

Question

I suspect I might need a function for that. I would like to return a Boolean. E.g., firstarray = ("haha", "ya", "test") and secondarray = ("haha", "no", "stop"), then return True. Thanks

Answer 1

Are There Any Matching Elements in Two Arrays? (One-Liner)
A safer yet less efficient way would probably be to loop through each element in one array and, in another (inner) loop, compare it to each element of the other array exiting the loops when a match is found.
Option Explicit
Sub Test()
Dim FirstArray() As Variant
FirstArray = Array("A", "ya", CVErr(xlErrNA), "test")
Dim SecondArray() As Variant
SecondArray = Array("sa", "aha", CVErr(xlErrNA), "stop")
If FoundMatchingElement(FirstArray, SecondArray) Then
Debug.Print "True"
Else
Debug.Print "False"
End If
' Result:
' False ' ... since error values are excluded from the comparison
End Sub
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
' Purpose: Returns a boolean indicating whether two arrays ('Arr1', 'Arr2')
' have a same element.
' Remarks: 'Application.Match' is case-insensitive i.e. 'A = a'.
' Error values will not be considered.
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
Function FoundMatchingElement( _
Arr1() As Variant, _
Arr2() As Variant) _
As Boolean
FoundMatchingElement _
= Application.Count(Application.Match(Arr1, Arr2, 0)) > 0
End Function

Answer 2

Please, use the next function. It does what you want without any iteration. It returns True if any of their elements are common to both of them:
Function MatchArrayElement(arr1, arr2) As Boolean
Dim arrMtch: arrMtch = Application.IfError(Application.match(arr1, arr2, 0), "x") 'place "x" instead of error (not matching elements)
MatchArrayElement = UBound(filter(arrMtch, "x", False)) > -1
End Function
It can be used in the next way:
Sub testMatchArrEl()
Dim arr1, arr2
arr1 = Array("hah", "ya", "test")
arr2 = Array("haha", "no", "stop")
Debug.Print MatchArrayElement(arr1, arr2)
End Sub
But if you need checking if a specific element/string exists in an array, you can use the following function:
Function arrElementMatch(El, arr) As Boolean
Dim mtch: mtch = Application.match(El, arr, 0)
arrElementMatch = Not IsError(mtch)
End Function
It can be checked in the next way:
Debug.Print arrElementMatch("haha", arr1), arrElementMatch("hah", arr1)
To check if the element exists in both array, try using:
Debug.Print arrElementMatch("haha", arr1) And arrElementMatch("haha", arr2)
Please, send some feedback after using it.
If something not clear enough, do not hesitate to ask for clarifications...