UBOUND


Returns the upper bound of an array's dimension

Syntax:
declare function Ubound ( array() as any, byval dimension as integer = 1 ) as integer

Usage:
result = Ubound( array [, dimension ] )

Parameters:
array
an array of any type
dimension
the dimension to get upper bound of

Return Value:
Returns the upper bound of an array's dimension.

Description:
Ubound returns the largest value that can be used as an index into a particular dimension of an array.

Array dimensions are numbered from one (1) to n, where n is the total number of dimensions. If dimension is not specified, Ubound will return the upper bound of the first dimension.

If dimension is zero (0), Ubound returns n, the number of dimensions in the array. For any other dimension values outside of the valid range 1..n, the result is -1. This can be used to detect the number of dimensions of variable-length arrays, and in combination with the result of Lbound() for such cases, whether a given dimension exists, or whether the array is empty (zero dimensions). See the Lbound page for more information.

Examples:

Dim array(-10 To 10, 5 To 15, 1 To 2) As Integer

Print UBound(array) 'returns 10
Print UBound(array, 2) 'returns 15
Print UBound(array, 3) 'returns 2


'' determining the size of an array
Dim As Short array(0 To 9)
Dim As Integer arraylen, arraysize

arraylen = UBound(array) - LBound(array) + 1
arraysize = arraylen * SizeOf( Short )

Print "Number of elements in array:", arraylen    '10
Print "Number of bytes used in array:", arraysize '10 * 2 = 20


'' determining the size of a multi-dimensional array
Dim As Long array4D(1 To 2, 1 To 3, 1 To 4, 1 To 5)
Dim As Integer arraylen, arraysize


arraylen = (UBound(array4D, 4) - LBound(array4D, 4) + 1) _
         * (UBound(array4D, 3) - LBound(array4D, 3) + 1) _
         * (UBound(array4D, 2) - LBound(array4D, 2) + 1) _
         * (UBound(array4D, 1) - LBound(array4D, 1) + 1)

arraysize = arraylen * SizeOf( Long )

Print "Number of elements in array:", arraylen    '2 * 3 * 4 * 5 = 120
Print "Number of bytes used in array:", arraysize '120 * 4 = 480


'' determining whether an array is empty
Dim array() As Integer

Print "lbound: "; LBound( array ), "ubound: "; UBound( array )  '' 1 and 0

If LBound( array ) > UBound( array ) Then
    Print "array is empty"
Else
    Print "array is not empty"
End If


Sub printArrayDimensions( array() As Integer )
    Print "dimensions: " & UBound( array, 0 )

    '' For each dimension...
    For d As Integer = LBound( array, 0 ) To UBound( array, 0 )
        Print "dimension " & d & ": " & LBound( array, d ) & " to " & UBound( array, d )
    Next
End Sub

Dim array() As Integer
printArrayDimensions( array() )

Print "---"

ReDim array(10 To 11, 20 To 22)
printArrayDimensions( array() )


See also:
Back to Array Functions
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