在Perl中解引用多维数组的正确方法是什么？

Question

In my code I have a multidimensional array

       $rows[$x][$y]

I am passing it to a sub function with multiple uses but at some point that function will need to remove (pop) one of the elements from the main array.

I believe the proper way to pass it is by referencing it since I am passing more than just the array:

        filterout(\@rows, $y, $data );

But am unsure of the syntax to dereferencing it on the subroutine side.

Would appreciate any help, thanks as alway.

Answer 1

To pop from an array reference, use

my $last = pop @$aref;

Or, in more recent Perl versions,

my $last = pop $aref->@*;

To pop the inner array, you need to dereference the given element of the array reference:

my $last = pop @{ $aref->[$index] };

or

my $last = pop $aref->[$index]->@*;

Answer 2

It's an array ref pointing to an array of array refs pointing to arrays of scalars. So you'll need two de-references for a single element, one for a column and none for a row:

sub filterout(\@$$) {
     my($array_ref, $y, $data) = @_;

     # single element <row>,<col>
     $array_ref->[ <row >]->[ <column> ] = ...;

     # pop column of <row>
     pop(@{ $array_ref->[ <row> ] });

     # pop row
     pop(@{ $array_ref });
}

filterout(@rows, $y, $data);

Note the prototype, which makes filterout() work like push() .