#!/usr/bin/perl

use strict;

my $data = 'gi|12345678|ref|NP_001234.1|';
my @data = split /\|/, $data;
my $number = $data[1];

##</code><code>##

#!/usr/bin/perl

use strict;

my $data = 'gi|12345678|ref|NP_001234.1|';
my $number = (split(/\|/, $data))[1];