in reply to deep copy, not deep create

I agree with saintmike. What you want to do is better using OO. To use the approach you are now, you can do something like this. See my deepmerge function. It is not complete, but works for your sample data. To complete it you need to handle all data types.

#!/usr/bin/perl use strict; use Data::Dumper; my %europe = ( skin => "euro-white", language => { default => "euro-englisch", instrument => "euro-clarinet", }, politics => "euro-democratic", ); my %german = ( skin => "de-white", language => { default => "de-german" } ); my %bavarian = ( skin => "bav-white", language => { default => "bav-bavarian" } ); # this is not enough, german/language overwrites # the complete hash of euro/language my %woman = %europe; deepmerge(\%woman, \%german); deepmerge(\%woman, \%bavarian); print Dumper(\%woman); # result is this: # $VAR1 = { # 'skin' => 'bav-white', # 'politics' => 'euro-democratic', # 'language' => { # 'default' => 'bav-bavarian' # ** this is not here: instrument => "euro-clarinet", # } # }; unless ($woman{language}->{instrument}) { die "Error: Language instrument is not there"; } else { print "It worked\n"; } sub deepmerge { my ($into, $this) = @_; for my $k (keys %$this) { if (defined $k and exists $into->{$k} and defined $into->{$k} and ref($into->{$k}) eq 'HASH' and ref($this->{$k}) eq 'HASH') { deepmerge($into->{$k}, $this->{$k}); } elsif (defined $k) { $into->{$k} = $this->{$k}; } } }