O'Reilly logo

VB.NET Language in a Nutshell, Second Edition by Steven Roman PhD, Paul Lomax, Ron Petrusha

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

Name

ReDim Statement

Syntax

ReDim [Preserve] varname(subscripts) _
                 [, varname(subscripts)  ...
Preserve (optional; Keyword)

Preserves the data within an array when changing the only or last dimension

varname (required; String literal)

Name of the variable

subscripts (required; Numeric)

Number of elements and dimensions of the array, using the syntax:

                           upper [, upper] ...

The number of upper bounds specified is the number of dimensions. Each upper bound specifies the size of the corresponding coordinate.

Description

Used within a procedure to resize and reallocate storage space for an array

Rules at a Glance

  • Arrays can be sized or resized using the ReDim statement. There is no limit to the number of times you can redimension a dynamic array.

  • The dimension cannot be changed, nor can the data type of the array be changed.

  • If you do not use the Preserve keyword in redimensioning the array, you can resize any of the coordinates of the array.

  • Use of the Preserve keyword allows you to retain the current values within the array, but it also allows you to resize only the last coordinate of an array.

  • You can redimension an array in a called procedure if you pass the array to the procedure by reference. For example:

    Public Sub Main Dim lArr( ) AS Object = {1,2,3,4,5,6,7,8,9,10} Dim lNum As Long ResizeArray(lArr) for each lNum in lARr Console.WriteLine(lNum) Next End Sub Public Sub ResizeArray(ByRef arr( ) As Object) ReDim Preserve arr(15) arr(10) = 20 arr(11) = 50 arr(12) = 80 arr(13) = 90 arr(14) ...

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required