Append last array element in Perl

i want to add a newline to the lastest element of an array
i have tried this :

$array[-1] .= "\n";

but it doesn’t work and i get the following error message :

Modification of non-creatable array value attempted, subscript -1

i have tried a few other methods as well (without .=), without success.
should i try splice ?

thanks !

example of what i want :

@array = (
  "one",
  "two",
  "n",
  "last\n",  # i want the newline to be added here
);

>Solution :

You can use $array[$#array] .= "\n"; to change last entry but make sure you are checking if array is not empty.

use strict;
use warnings;

use Data::Dumper;

my @array = (
  "one",
  "two",
  "n",
  "last",
);

print Dumper(\@array);

if ($#array != -1) {
    $array[$#array] .= "\n";
}

print Dumper(\@array);