PERL: How do i print an associative matrix?

Shell Programming and Scripting
1

Hello guys,

I have in PERL an associative 2-dimensional array, called matrix. The array (actually the matrix) is made up like this

matrix[a][c] = x;
matrix[a][d] = y;
matrix[c] = w;
matrix[d] = z;
...

but the names a, b, c, d are set just at runtime.

The question is: how can i get all the keys of the matrix (i.e. a, b, c, d) and print the all matrix?

Thank you very much for your help!

   Sergio
2

What are a, b, c, d? Numbers or strings?

Assuming that is strictly 2-dimensional and all strings, that can be

$matrix = { a => {c => 'x', d => 'y'}, b => {c => 'w', d => 'z'}};

foreach my $key1 (keys %$matrix) {
foreach my $key2 (keys %{$matrix->{$key1}}) {
print $matrix->{$key1}{$key2}, " ";
}
print "\n";
}

For the keys, you can put a hash inside the loop and append each key each time one is retrieved. At the end, you simply iterate the hash to get back the keys.

3

Yes they are strings. Thank you very much cbkihong!

The code you posted nearly works (there were some typing errors). I post the correct code:

foreach $key1 (keys %matrix) {
        foreach $key2 (keys %{%matrix->{$key1}}) {
                print "\$matrix{$key1}{$key2} = $matrix{$key1}{$key2},  ";                            
                } 
        print"\n";                                                                                   
        }

Hope this will help sombody else.

Cheers,

 Sergio