Why does Perl complain “Use of implicit split to @_ is deprecated”?

Question

This code triggers the complaint below:

#!/usr/bin/perl 
use strict;
use warnings;

my $s = \"aaa bbb\";
my $num_of_item = split(/\\s+/, $s) ;
print $num_of_         


        

Answer 1

You are using split in scalar context, and in scalar context it splits into the @_ array. Perl is warning you that you may have just clobbered @_. (See perldoc split for more information.)

To get the number of fields, use this code:

my @items = split(/\s+/, $s);
my $num_of_item = @items;

or

my $num_of_item = () = split /\s+/, $s, -1;

Note: The three-argument form of split() is necessary because without specifying a limit, split would only split off one piece (one more than is needed in the assignment).