This is easy, at least if you want a 1-based, 1D or 2D variant array:
Sub StuffVArr()
Dim v() As Variant
Dim q() As Variant
v = Evaluate("=IF(ISERROR(A1:K1), 13, 13)")
q = Evaluate("=IF(ISERROR(A1:G48), 13, 13)")
End Sub
Byte arrays also aren't too bad:
Private Declare Sub FillMemory Lib "kernel32" Alias "RtlFillMemory" _
(dest As Any, ByVal size As Long, ByVal fill As Byte)
Sub StuffBArr()
Dim i(0 To 39) As Byte
Dim j(1 To 2, 5 To 29, 2 To 6) As Byte
FillMemory i(0), 40, 13
FillMemory j(1, 5, 2), 2 * 25 * 5, 13
End Sub
You can use the same method to fill arrays of other numeric data types, but you're limited to only values which can be represented with a single repeating byte:
Sub StuffNArrs()
Dim i(0 To 4) As Long
Dim j(0 To 4) As Integer
Dim u(0 To 4) As Currency
Dim f(0 To 4) As Single
Dim g(0 To 4) As Double
FillMemory i(0), 5 * LenB(i(0)), &HFF 'gives -1
FillMemory i(0), 5 * LenB(i(0)), &H80 'gives -2139062144
FillMemory i(0), 5 * LenB(i(0)), &H7F 'gives 2139062143
FillMemory j(0), 5 * LenB(j(0)), &HFF 'gives -1
FillMemory u(0), 5 * LenB(u(0)), &HFF 'gives -0.0001
FillMemory f(0), 5 * LenB(f(0)), &HFF 'gives -1.#QNAN
FillMemory f(0), 5 * LenB(f(0)), &H80 'gives -1.18e-38
FillMemory f(0), 5 * LenB(f(0)), &H7F 'gives 3.40e+38
FillMemory g(0), 5 * LenB(g(0)), &HFF 'gives -1.#QNAN
End Sub
If you want to avoid a loop in other situations, it gets even hairier. Not really worth it unless your array is 50K entries or larger. Just set each value in a loop and you'll be fast enough, as I talked about in an earlier answer.