johngg@shiraz:~ > perl -Mstrict -Mwarnings -E '
my %colours    = (
   blue   => q{1},
   green  => q{2},
   red    => q{3},
   pink   => q{4},
   purple => q{5},
   );

my @numbers    = qw{ 1 2 3 4 5 };
my $pick       = $numbers[ int rand @numbers ];
say qq{Number $pick chosen};

my( $colour )  = grep { $colours{ $_ } eq $pick } keys %colours;
say qq{Colour is $colour};'
Number 2 chosen
Colour is green