Re: Looping through an array with FOR EACH

[Brian G <brian@xxxxxxxxxxxxxxxx>]

On 1/15/26 15:21, Gianluigi wrote:
> Il 15/01/26 23:26, Benoît Minisini ha scritto:
> > Sorry, I never thought I would have to explain that, because arrays 
> > work the same way in every language - except javascript, but who said 
> > is was a serious language?
> >
> > An array is a list of values of the same datatypes that are stored 
> > consecutively in memory. Why? Because it's the easiest and fastest 
> > way to store and access its contents.
> >
> > It's a basic data structure that is even often handled by specific 
> > CPU instructions, especially on x86.
> >
> > And so values are indexed by their position, and so it's logical to 
> > enumerate them in the index order. Which other order could you use?
> >
> > And of course, if you modify the array while you enumerate it, you 
> > must use your brain to understand which wrong things could happen.
> >
> > Regards,
> >
> > --
> > Benoît Minisini.
>
> Dear Benoit,
>
> I apologize for creating all this confusion.
>
> It all started with a forum user writing that it would have been 
> better to loop through the array with For Each.
> Then I remembered your warning (which, as usual, I misunderstood).
>
> But at this point, you need to explain to me why the FOR EACH loop 
> would be better than the one I suggested:
>
> [code] Public Sub Main()
>
>   Dim aAreas As New String[][] ' The dynamic matrix
>   Dim r, c, e, i As Integer
>   ' Array of support to the random filling of the matrix with pseudo 
> names
>   Dim aNomi As String[] = ["Ful", "Gal", "Doc", "Ech", "All", "Bil", 
> "Val", "Mal", "Cec", "Lol", "Nib"]
>
>   r = 5 ' six rows
>   ' Initializes the random number generator
>   Randomize
>   ' Loop to populate the dynamic array
>   For e = 0 To r
>     ' Resize the array
>     aAreas.Resize(e + 1)
>     ' Instantiates a new internal array
>     aAreas[e] = New String[]
>     ' random number of columns
>     c = Rand(0, 8)
>     ' Loop to populate the array
>     For i = 0 To c
>       ' Resize the array
>       aAreas[e].Resize(i + 1)
>       ' Generate random names, but with number of row and column for 
> the control
>        aAreas[e][i] = aNomi[Rand(0, 10)] & "(C" & CStr(i + 1) & " R" & 
> CStr(e + 1) & ")"
>     Next
>   Next
>   ' Read the jagged matrix
>   For r = 0 To aAreas.Max
>     For c = 0 To aAreas[r].Max
>       Print aAreas[r][c];;
>     Next
>     Print
>   Next
>
>   ' This may be better <----------------------???
>   Print "=============================================================="
>   For Each area As String[] In aAreas
>         For Each entry As String In area
>             Print entry;;
>         Next
>         Print
>     Next
>
> End [/code]
>
> With Best Regards
> Gianluigi
It was not Ben that suggested that It was me, and it was because the 
fellow wanted to use fixed array size entry within a dynamic array.

I suggested it because it was easier to understand. I was not commenting 
on your code, only on the code I presented of which you only quote the 
last paragraph example

For Each area As String[] In aAreas
        For Each entry As String In area
            Print entry;;
        Next
        Print
    Next


--
~~~~ Brian

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