Information.UBound(Array, Int32) Method

Reference

Definition

Namespace:: Microsoft.VisualBasic

Assembly:: Microsoft.VisualBasic.Core.dll

Assembly:: Microsoft.VisualBasic.dll

Source:: Information.vb

Source:: Information.vb

Source:: Information.vb

Important

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Returns the highest available subscript for the indicated dimension of an array.

public static int UBound (Array Array, int Rank = 1);

static member UBound : Array * int -> int

Public Function UBound (Array As Array, Optional Rank As Integer = 1) As Integer

Parameters

Array: Array

Required. Array of any data type. The array in which you want to find the highest possible subscript of a dimension.

Rank: Int32

Optional. Integer. The dimension for which the highest possible subscript is to be returned. Use 1 for the first dimension, 2 for the second, and so on. If Rank is omitted, 1 is assumed.

Returns

Int32

Integer. The highest value the subscript for the specified dimension can contain. If Array has only one element, UBound returns 0. If Array has no elements, for example if it is a zero-length string, UBound returns -1.

Exceptions

ArgumentNullException

Array is Nothing.

RankException

Rank is less than 1, or Rank is greater than the rank of Array.

Examples

The following example uses the UBound function to determine the highest available subscript for the indicated dimension of an array.

Dim highest, bigArray(10, 15, 20), littleArray(6) As Integer
highest = UBound(bigArray, 1)
highest = UBound(bigArray, 3)
highest = UBound(littleArray)
' The three calls to UBound return 10, 20, and 6 respectively.

Remarks

Since array subscripts start at 0, the length of a dimension is greater by one than the highest available subscript for that dimension.

For an array with the following dimensions, UBound returns the values in the following table:

Dim a(100, 5, 4) As Byte

Call to UBound	Return value
`UBound(a, 1)`	100
`UBound(a, 2)`	5
`UBound(a, 3)`	4

You can use UBound to determine the total number of elements in an array, but you must adjust the value it returns to account for the fact that the subscripts start at 0. The following example calculates the total size of the array a in the preceding example:

Dim total As Integer  
total = (UBound(A, 1) + 1) * (UBound(A, 2) + 1) * (UBound(A, 3) + 1)

The value calculated for total is 3030, which is 101 * 6 * 5.

Applies to

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