Information.LBound Method

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

Namespace: Microsoft.VisualBasic
Assembly: Microsoft.VisualBasic (in microsoft.visualbasic.dll)

public static int LBound (
	Array Array,
	[OptionalAttribute] int Rank
public static int LBound (
	Array Array, 
	/** @attribute OptionalAttribute() */ int Rank
public static function LBound (
	Array : Array, 
	Rank : int
) : int
Not applicable.



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


Optional. Integer. The dimension for which the lowest 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.

Return Value

Integer. The lowest value the subscript for the specified dimension can contain. LBound always returns 0 as long as Array has been initialized, even if it has no elements, for example if it is a zero-length string. If Array is Nothing, LBound throws an ArgumentNullException.

For more detailed information, see the Visual Basic topic LBound Function (Visual Basic).

Since array subscripts start at 0, the lowest available subscript for every dimension is always 0.

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

Dim a(100, 5, 4) As Byte

Call to LBound

Return value

LBound(a, 1)


LBound(a, 2)


LBound(a, 3)


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

Dim lowest, bigArray(10, 15, 20), littleArray(6) As Integer
lowest = LBound(bigArray, 1)
lowest = LBound(bigArray, 3)
lowest = LBound(littleArray)
' All three calls to LBound return 0.

Windows 98, Windows Server 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 2.0, 1.0

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