Question

In the following example:

my $info = 'NARIKANRU';
my @first_one = split /,/, $info;
print "$first_one[$#first_one]$first_one[$#first_one-1]\n";

The output is:

NARIKANRUNARIKANRU

I am not sure if this is correct because there is only one element in @first_one and $#first_one is the index of that element.

Given that $#first_one is not equal to $#first_one - 1, why is the single element in @first_one being printed twice?

Answer 1

The output is correct. There are no commas in $info so split returns a list consisting of a single element.

$#first_one is the index of the last (and in this case also first and only) element of @first_one. With a single element, $#first_one is 0. Therefore, $first_one[$#first_one] is $first_one[0].

Also, $first_one[$#first_one-1] is $first_one[-1], i.e. the short hand way of referring to the last element of an array.

Of course, things would not have worked out this way had $[ been set to some other value than the default. Apparently, things work unless $[ is negative.

See also perldoc perldata.

Finally, you ask if there is anything wrong in your code. From what I can see, you are not using strict and warnings. You should.