【VBA】一次元配列と一次元配列を結合する

' Concatenate two 1D arrays safely and return as Variant array
' 2つの一次元配列を安全に結合して返す
Public Function Merge1DArrays( _
	ByRef ary1 As Variant, _
	ByRef ary2 As Variant) As Variant

	Dim result() As Variant
	Dim size1 As Long, size2 As Long
	Dim i As Long
	
	' Nullチェック｜Handle Null
	If IsEmpty(ary1) Then
		If IsEmpty(ary2) Then
			JoinOneDimAry = Array()
			Exit Function
		Else
			JoinOneDimAry = ary2
			Exit Function
		End If
	End If
	If IsEmpty(ary2) Then
		JoinOneDimAry = ary1
		Exit Function
	End If
	
	' サイズ算出｜Compute sizes
	size1 = UBound(ary1) - LBound(ary1) + 1
	size2 = UBound(ary2) - LBound(ary2) + 1
	ReDim result(1 To size1 + size2)
	
	' コピー処理｜Copy elements
	For i = 1 To size1
		result(i) = ary1(LBound(ary1) + i - 1)
	Next i
	For i = 1 To size2
		result(size1 + i) = ary2(LBound(ary2) + i - 1)
	Next i
	
	JoinOneDimAry = result
End Function