Hash Ref Initialization

hypochrismutreefuzz has asked for the wisdom of the Perl Monks concerning the following question:

How is the best way to initialize a hash_ref?

my $hash_ref = {
    hack    =>    slash,
    frobozz =>    portrait,
    candle  =>    lit,
};

my @keys = keys %$hash_ref;
my $hash_copy = {};
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Now say we want $hash_copy to contain a copy of all the information in $hash_ref. Which of these is preferable?

@{ $hash_copy } { @keys } = @{ $hash_ref } { @keys };


$hash_copy->{$_} = $hash_ref->{$_} for @keys;
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Comment on Hash Ref Initialization Select or Download Code

Replies are listed 'Best First'.
Re: Hash Ref Initialization by eric256 (Parson) on Dec 10, 2007 at 20:36 UTC
How about `$hash_copy = { %$hash_original }`? ___________ Eric Hodges	[reply] [d/l]
Re: Hash Ref Initialization by mwah (Hermit) on Dec 10, 2007 at 20:51 UTC
simply by 'hash intialization' (%$hash_copy = %$hash_ref): `use strict; use warnings; my $hash_ref = { hack => 'slash', frobozz => 'portrait', candle => 'lit', }; my $hash_copy; %$hash_copy = %$hash_ref; map $_ .= '_mod', values %$hash_copy; # encouraged in v.5.10 print map "$_ => $hash_ref->{$_} \n", keys %$hash_ref; print map "$_ => $hash_copy->{$_} \n", keys %$hash_copy;` [download] Regards mwa	[reply] [d/l]
Re: Hash Ref Initialization by Roy Johnson (Monsignor) on Dec 10, 2007 at 20:50 UTC
If your hashref could contain other refs, you might want to look at Clone and/or Data::COW. Caution: Contents may have been coded under pressure.	[reply]