LBound Method

Information.LBound Method (Array, Int32)


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,
	int Rank = 1


Type: System.Array

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

Type: System.Int32

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

Type: System.Int32

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.

Exception Condition

Array is Nothing.


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

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.

.NET Framework
Available since 1.1
Available since 2.0
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