vba - checking for empty array [duplicate]

Question

Function IsVarArrayEmpty(anArray As Variant)

Dim i As Integer

On Error Resume Next
    i = UBound(anArray, 1)
If Err.Number = 0 Then
    IsVarArrayEmpty = False
Else
    IsVarArrayEmpty = True
End If

End Function

It is returning true for uninitialized and false for initialized. I want to see if it has any data/content. However, the problem is I feel the above code is returning false even when there is no data in the array. How do I check that?

(I tried setting string s equal to the byte array. That was "". That means the array is empty, right?)

Answer 1

I personally use this - now if you ReDim an array with ReDim v (1 To 5) As Variant, isArrayEmpty(v) will return false because v has 5 items, although they are all uninitialised.

Public Function isArrayEmpty(parArray As Variant) As Boolean
'Returns true if:
'  - parArray is not an array
'  - parArray is a dynamic array that has not been initialised (ReDim)
'  - parArray is a dynamic array has been erased (Erase)

  If IsArray(parArray) = False Then isArrayEmpty = True

  On Error Resume Next

  If UBound(parArray) < LBound(parArray) Then
      isArrayEmpty = True
      Exit Function
  Else
      isArrayEmpty = False
  End If

End Function

Answer 2

I am simply pasting below the code by the great Chip Pearson.
Also check out his page on array functions.

I hope this helps.

Public Function IsArrayEmpty(Arr As Variant) As Boolean
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
' IsArrayEmpty
' This function tests whether the array is empty (unallocated). Returns TRUE or FALSE.
'
' The VBA IsArray function indicates whether a variable is an array, but it does not
' distinguish between allocated and unallocated arrays. It will return TRUE for both
' allocated and unallocated arrays. This function tests whether the array has actually
' been allocated.
'
' This function is really the reverse of IsArrayAllocated.
'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''

    Dim LB As Long
    Dim UB As Long

    err.Clear
    On Error Resume Next
    If IsArray(Arr) = False Then
        ' we weren't passed an array, return True
        IsArrayEmpty = True
    End If

    ' Attempt to get the UBound of the array. If the array is
    ' unallocated, an error will occur.
    UB = UBound(Arr, 1)
    If (err.Number <> 0) Then
        IsArrayEmpty = True
    Else
        ''''''''''''''''''''''''''''''''''''''''''
        ' On rare occassion, under circumstances I
        ' cannot reliably replictate, Err.Number
        ' will be 0 for an unallocated, empty array.
        ' On these occassions, LBound is 0 and
        ' UBound is -1.
        ' To accomodate the weird behavior, test to
        ' see if LB > UB. If so, the array is not
        ' allocated.
        ''''''''''''''''''''''''''''''''''''''''''
        err.Clear
        LB = LBound(Arr)
        If LB > UB Then
            IsArrayEmpty = True
        Else
            IsArrayEmpty = False
        End If
    End If

End Function