longest, shortest, map wrong

Shell Programming and Scripting
1

Hi Everyone,
a.txt

cola,colb1111
601030,CEL
6031,CEL
60103,CEL

Would like to find the longest field colb1111, and shortest, so the output is 6, 4

my code:

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

my %prefix_to_contry = ();
my $key;
open(FH,'/root/a.txt') or die "$!";
while(<FH>){
        chomp;
        my @fields = split(/,/);
        $prefix_to_contry{$fields[0]} = $fields[1];
}
my ( $shortest, $longest ) = ( sort { $a <=> $b } map { length } keys %prefix_to_contry )[ 0, -1 ];
print "$shortest  $longest\n";exit;

but the output is shortest=4, longest=9. where is wrong with this code.

Thanks

---------- Post updated at 08:03 PM ---------- Previous update was at 11:36 AM ----------

any advice, thanks

---------- Post updated at 09:11 PM ---------- Previous update was at 08:03 PM ----------

find the anwer already.

before chmop, add next if $. < 2;