My preferred way is a bit long, but has some advantages over the other answers:
Here it is:
Function combineArrays(ByVal toCombine As Variant, Optional ByVal newBase As Long = 1)
'Combines an array of one or more 1d arrays, objects, or values into a single 1d array
'newBase parameter indicates start position of new array (0, 1, etc.)
'Example usage:
'combineArrays(Array(Array(1,2,3),Array(4,5,6),Array(7,8))) -> Array(1,2,3,4,5,6,7,8)
'combineArrays(Array("Cat",Array(2,3,4))) -> Array("Cat",2,3,4)
'combineArrays(Array("Cat",ActiveSheet)) -> Array("Cat",ActiveSheet)
'combineArrays(Array(ThisWorkbook)) -> Array(ThisWorkbook)
'combineArrays("Cat") -> Array("Cat")
Dim tempObj As Object
Dim tempVal As Variant
If Not IsArray(toCombine) Then
If IsObject(toCombine) Then
Set tempObj = toCombine
ReDim toCombine(newBase To newBase)
Set toCombine(newBase) = tempObj
Else
tempVal = toCombine
ReDim toCombine(newBase To newBase)
toCombine(newBase) = tempVal
End If
combineArrays = toCombine
Exit Function
End If
Dim i As Long
Dim tempArr As Variant
Dim newMax As Long
newMax = 0
For i = LBound(toCombine) To UBound(toCombine)
If Not IsArray(toCombine(i)) Then
If IsObject(toCombine(i)) Then
Set tempObj = toCombine(i)
ReDim tempArr(1 To 1)
Set tempArr(1) = tempObj
toCombine(i) = tempArr
Else
tempVal = toCombine(i)
ReDim tempArr(1 To 1)
tempArr(1) = tempVal
toCombine(i) = tempArr
End If
newMax = newMax + 1
Else
newMax = newMax + (UBound(toCombine(i)) + LBound(toCombine(i)) - 1)
End If
Next
newMax = newMax + (newBase - 1)
ReDim newArr(newBase To newMax)
i = newBase
Dim j As Long
Dim k As Long
For j = LBound(toCombine) To UBound(toCombine)
For k = LBound(toCombine(j)) To UBound(toCombine(j))
If IsObject(toCombine(j)(k)) Then
Set newArr(i) = toCombine(j)(k)
Else
newArr(i) = toCombine(j)(k)
End If
i = i + 1
Next
Next
combineArrays = newArr
End Function