How to redim a two or three dimensional array?

2013-08-25

Question

_{Sunday, August 25, 2013 9:27 AM}

Hello;

I'm used to write :

redim preserve all_clr(intcounter1)

But when I tried to use with two dimensional array it didn't work.

SO how I redim a two or three dimensional array?

All replies (4)

_{Sunday, August 25, 2013 10:02 AM ✅Answered}

Hi,

If you wanna re-dim a two dimensional array, you have to do this:

Module Module1
 
    Sub Output(numbers(,) As Integer)
        For y As Integer = 0 To numbers.GetLength(0) - 1
            For x As Integer = 0 To numbers.GetLength(1) - 1
                Console.Write(numbers(y, x) & "  ")
            Next
            Console.WriteLine()
        Next
    End Sub
 
    Sub Main()
 
        Dim numbers(1, 1) As Integer
        Dim n As Integer = 1
 
 
        For i As Integer = 0 To 1
            For j As Integer = 0 To 1
                numbers(i, j) = n
            Next
            n += 1
        Next
 
        'Output
        Output(numbers)
 
        'Changed
        ReDim Preserve numbers(1, 2)
 
        'Assign values
        numbers(0, 2) = 100
        numbers(1, 2) = 200
 
        Console.WriteLine("Changed Later=======")
        'Output
        Output(numbers)
    End Sub
End Module

But plz notice that if you shorten the two-dimision array, you should ONLY change the MOST-RIGHT dimision number:

Module Module1
 
    Sub Output(numbers(,) As Integer)
        For y As Integer = 0 To numbers.GetLength(0) - 1
            For x As Integer = 0 To numbers.GetLength(1) - 1
                Console.Write(numbers(y, x) & "  ")
            Next
            Console.WriteLine()
        Next
    End Sub
 
    Sub Main()
 
        Dim numbers(2, 2) As Integer
 
 
        For i As Integer = 0 To 2
            For j As Integer = 0 To 2
                numbers(i, j) = i * j
            Next
        Next
 
        'Output
        Output(numbers)
 
        'Redim Preserve numbers(1,1)——This is wrong! You cannot change the first dimision
        ReDim Preserve numbers(2, 1)
 
        Console.WriteLine("Changed Later=======")
        'Output
        Output(numbers)
    End Sub
End Module

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_{Sunday, August 25, 2013 9:46 AM}

From Help.

Resizing with Preserve. If you use Preserve, you can resize only the last dimension of the array, and for every other dimension you must specify the same bound it already has in the existing array.

For example, if your array has only one dimension, you can resize that dimension and still preserve all the contents of the array, because you are changing the last and only dimension. However, if your array has two or more dimensions, you can change the size of only the last dimension if you use Preserve.

Regards Les, Livingston, Scotland

_{Sunday, August 25, 2013 2:26 PM}

C# and VB have parity.

It means that almost all things can be done in both program languages.

C# has the possibility of unsafe code as legacy from C++ which is not in VB; VB has the Redim from older VB versions which is not in C#.

Nobody who knows a little bit more about those regrets it that it is has no parity.

Try to avoid the Redim and go for a class approach as is thousand times written in this forum.

Success
Cor

_{Thursday, August 29, 2013 9:57 PM}

Consider:

Public Class Form1
    Dim ar1 As New List(Of Integer)
    Dim ar2 As New List(Of Integer)
    Dim ar3 As New List(Of String)

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles Me.Load
        ar3.Add("string 1")
        ar1.Add(ar3.Count - 1)
        ar3.Add("string 2")
        ar2.Add(ar3.Count - 1)
        ar3.Add("string 3")
        ar1.Add(ar3.Count - 1)
        ar3.Add("string 4")
        ar2.Add(ar3.Count - 1)

        For i = 0 To ar1.Count - 1
            Debug.Print("{0} | {1}", ar3(ar1(i)), ar3(ar2(i)))
        Next
        Stop
    End Sub
End Class

Which can be modified according to what you know of the depth of each dimension.

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How to redim a two or three dimensional array?

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