1 A
2 B

##</code><code>##

{
  1 => "A",
  2 => "B", 
}

##</code><code>##

use strict; 
use Data::Dumper;

my $s = "1 A\n2 B\n"; 

my %h =map { $1 => $2 } $s =~ /(\d+)\s+(\S+)/mg;
print Dumper(\%h);

##</code><code>##

$VAR1 = {
          '2' => 'B'
        };