LBound Function (Visual Basic)

Article
11/18/2006

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

Public Function LBound( _
   ByVal Array As System.Array, _
   Optional ByVal Rank As Integer = 1 _
) As Integer

Parameters

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

Rank
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.

Exceptions

Exception type	Error number	Condition
ArgumentNullException	9	Array is Nothing.
RankException	9	Rank < 1 or Rank is greater than the rank of Array.

See the "Error number" column if you are upgrading Visual Basic 6.0 applications that use unstructured error handling. (You can compare the error number against the Number Property (Err Object).) However, when possible, you should consider replacing such error control with Structured Exception Handling Overview for Visual Basic.

Remarks

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)`	0
`LBound(a, 2)`	0
`LBound(a, 3)`	0

Example

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.

Requirements

Namespace: Microsoft.VisualBasic

Module: Information

Assembly: Visual Basic Runtime Library (in Microsoft.VisualBasic.dll)

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