#! /usr/bin/perl -lw
#
use strict ;
my $key = "b" ;
printf "key=%s, value is %s\n", $key, get_value($key) ;

sub get_value {
  my $key = shift ;
  my @ta = ("a x", "b y", "c z") ; # test array

  return (map{ /^$key/ and s/^$key//, $_ } grep( /^$key/, @ta))[1] ;
}