Your program has a couple of problems:
First, you are splitting on comma's, then the pc no (the first field) has index 0, index 1 gets you the ip-address.
Next, you are reading the entire second file for each line found in the first file, that will give you some serious I/O for big files.
Perl is not very good at finding out whether something is in a list. If you want to do that, think of a hash in stead. Lists are for processing bulk data element by element. Keeping this in mind, let's rewrite the program.
Assuming you have two files, pcs_old.csv and pcs_new.csv, starting with the opening stuff:
use strict;
use warnings;
open (OLD, "<pcs_old.csv");
open (NEW, "<pcs_new.csv");
my %old; # where pc numbers will get stored...
Read the old file line by line...
while (<OLD>) {
chomp;
my @fields = split /,/;
my $pc = $fields[0]; # get the first field
$pc =~ s/"//g; # get rid of the quotes
$old {$pc} = 1; # make an entry in the hash
}
Now do the same for the new pc file, but instead of storing them, see if an entry exists in the database with old pc's:
while (<OLD>) {
chomp;
my @fields = split /,/;
my $pc = $fields[0]; # get the first field
$pc =~ s/"//g; # get rid of the quotes
if (! exists $old {$pc}) {
# the new pc file has a pc which did not exist
# in the old pc file
print "new PC found: $pc\n";
}
}
# and cleanup
close (OLD);
close (NEW);
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