Print 2 Dimensional Array in Loop Perl

Question

This is how i append data into the array :

push @cordinate_and_link, ($cordinate , $link); 

So if i print @cordinate_and_link i get something like:

172193 1 19601 2 14835 3 4758 4 ...

I will like have a loop which can loop only the first column[0] and produce all values.

This is what i have been trying:

foreach my $cordinate ( $cordinate_and_link[0]) {
            print "$cordinate";
        } 

But this statement prints only the last value in the row "4758" as many times as the loop runs.

Answer 1

You are currently appending two values to @cordinate_and_link which sit next to each other – they are not in separate columns. To make clear that they are in two different columns, we push an anonymous arrayref [...] instead:

push @cordinate_and_link, [$cordinate , $link]; 

Parens () do not create arrays or tuples in Perl.

Later, we can loop over all rows and only print the first column in each row:

foreach my $cordinate (@cordinate_and_link) {
    print $cordinate->[0];
} 

Answer 2

The code in your post flattens your list into a one-dimensional array:

push @coordinate_and_link, ($coordinate , $link);

which would require a row-major order expression to get at 'column 0'.

I think you want this:

push @coordinate_and_link, [$coordinate, $link];

In which case you would iterate over it like this:

for my $row (@coordinate_and_link) {
    print "$row->[0]\n";
}

You can iterate over that structure a lot of ways, that is just one.

EDIT: Fixed typo.