2D Arrays

[rbulph]

Is there a simple way to re-order the data in a 2D array by rows? e.g. in an array declared as "s(3,3) as string", move all the items with the first index as 0 to the end, and shunt the other items up on level as regards the first index.

[snarfblam]

Have you considered using jagged arrays? With jagged arrays you can treat different "rows" (if that is how you prefer to think of it) independently. For example...

[Color=Blue]Private Sub [/Color]Button1_Click([Color=Blue]ByVal [/Color]sender [Color=Blue]As [/Color]System.Object, _

    [Color=Blue]ByVal [/Color]e [Color=Blue]As [/Color]System.EventArgs) [Color=Blue]Handles [/Color]Button1.Click

   [Color=Green] 'Create empty array that can hold 3 rows

[/Color]    [Color=Blue]Dim [/Color]Test [Color=Blue]As [/Color]String()() = [Color=Blue]New [/Color]String(2)() {}

 

[Color=Green]    'Create and populate rows.[/Color]

    [Color=Blue]For [/Color]i [Color=Blue]As Integer [/Color]= 0 [Color=Blue]To[/Color] 2

        Test(i) = [Color=Blue]New [/Color]String(2) {} [Color=Green]'Create a row with 3 items[/Color]

 [Color=Green]

        'Populate row[/Color]

        [Color=Blue]For [/Color]j [Color=Blue]As Integer [/Color]= 0 [Color=Blue]To [/Color]2

            Test(i)(j) = Chr(65 + j + i * 3)[Color=Green] 'Set a single, unique character.[/Color][Color=Blue]

        Next

    Next[/Color]

 

    OutputArray(Test)

    MessageBox.Show("Click OK to swap")

 

   [Color=Green] 'Swap two rows

[/Color]    [Color=Blue]Dim [/Color]placeholder [Color=Blue]As [/Color]String() = Test(1)

    Test(1) = Test(0)

    Test(0) = placeholder

 

   OutputArray(Test)

[Color=Blue]End Sub[/Color]

 

[Color=Blue]Sub [/Color]OutputArray([Color=Blue]ByVal [/Color]data [Color=Blue]As [/Color]String()())

    txtOutput.Clear()

    [Color=Blue]For [/Color]i [Color=Blue]As Integer [/Color]= 0 [Color=Blue]To [/Color]UBound(data)

        [Color=Blue]For [/Color]j [Color=Blue]As Integer [/Color]= 0 [Color=Blue]To [/Color]UBound(data(i))

            txtOutput.Text &= data(i)(j) & "; "

        [Color=Blue]Next[/Color]

        txtOutput.Text &= Environment.NewLine

[Color=Blue]    Next

End Sub[/Color]

[/Code]

 

Another option might be to use Array.Copy to copy data from one row to another, provided that there is a relevant overload present. This would also require a second 1-D array to act a buffer.

[rbulph]

Thanks, that's useful. I wasn't aware of the possibility of doing this. Ideally I'd like to have the facility to rearrange both rows and columns, but I don't think there's a structure that will allow me to do this. Perhaps I will just have to reposition items one by one on one axis.