Perl: Assigning References to Array Elements in a Foreach Loop

Question

I really wanted to figure this out myself, but my face is now hurting from continually running into this brick wall.

I'm trying to load 9 text files, each consisting of a matrix of 7 rows of 7 characters seperated by spaces and then save each referenced matrix to an element in an array. I am reading in each file just fine, but when I go to access my array all of the elements are the same. I've been searching for a solution and either my question isn't answered anywhere, or (more likely) I'm not understanding the answer. Here's the problem section of my code:

my @boardarray = (1, 2, 3, 4, 5, 6, 7, 8, 9);
sub LoadBoards {
    my (@board, $infile, @allboards);
    my $i = 1;
    @allboards = @boardarray;
    foreach (@allboards) {
        my $infile = "board" . $i . "\.brd";
        open FILE, "< $infile" or die $!;
        my $line = 0;
        while (<FILE>) {
            chomp $_;
            my @chars = split (/ /,$_);
            $board[$line] = [@chars];
            $line++;
        }
    my $tempboard = \@board;
        DisplayOneBoard($tempboard); print ("\n");              #Test A
    $boardarray[$i-1] = \@board;                                #Problem line?
        DisplayOneBoard($boardarray[$i-1]); print ("\n");       #Test B
        DisplayOneBoard($boardarray[0]); print ("\n----\n");    #Test C
    $i++;
    }
}

-I've tried assinging variables as the elements of @boardarray with no change.
-I was using @boardarray in the foreach loop and changed it to the copied @allboards with no improvement.
I expect the 'Test A' and 'Test B' lines to be the same and for the 'Test C' line to stay the first matrix I loaded in. However, all three are the same for every iteration.
(For iteration 1 they are all matrix 1. For iteration 2 they are all matrix 2, etc.)
At the end all the elements are the exact same matrix (matrix 9).

Any assistance would be appreciated. Thanks.

Answer 1

The problem is that you are re-using the same @board each time through your loop. When you push a reference to that board onto @boardarray, you are pushing a reference pointing the same @board each time. The fix is simple, just move my @board to the inside of your foreach loop; this creates a new @board each time through.