#!/usr/bin/perl

use strict; # https://perlmonks.org/?node_id=11141469
use warnings;
use List::AllUtils qw( nsort_by );

my $pchr = 'KQRBNP';
my $w1 = 'QRKPNB';
my $w2 = join '', nsort_by { index $pchr, $_ } split //, $w1;
print "Given pchr = $pchr, then $w1 -> $w2\n";