http://www.perlmonks.org?node_id=274482


in reply to parse hash to sub

Because Perl automatically flattens hashes and arrays that are passed to subs, my %packages = $_[1]; doesn't access the entire %new_db hash, but only the first key of %new_db, which is why you're getting the odd number of elements error.

Do it this way instead:

new_packages($fcount,\%new_db); sub new_packages { my %packages = %{$_[1]}; ...
By passing %new_db as a hash-reference, $_[1] refers to the hash-ref, which is then de-referenced into the %packages hash like you want.

Most all of the time if you need to pass an array or hash into a sub you'll want to pass it by reference, not by value. :-)

Gary Blackburn
Trained Killer