Copying multi-level hash

mt2k has asked for the wisdom of the Perl Monks concerning the following question:

Help, I am hopelessly confused!!

Lets say that I have the following hash:

%hash = (
        'key1' => {
                        1 => {
                                'var' => 1,
                                1 => {
                                       'name1' => 'value3',
                                       'name2' => 'value2',
                                       'name3' => 'value3'
                                     }
                             },
                        2 => {
                                'var' => 1,
                                1 => {
                                       'name1' => 'value1',
                                       'name2' => 'value2',
                                       'name3' => 'value3'
                                     }
                             },
                        
                  }
        );
[download]

Now, how do I copy one part of this hash, such as the %hash{'key1'}{1} section??
Would it be done with one of these?:

1. %copy = %hash{'key1'}{1}
2. %copy = %{$hash{'key1'}{1}}
[download]

I really have no clue... I have just begun last week working with complex hashes and arrays, and I'm just a little confused! %-|

Comment on Copying multi-level hash Select or Download Code

Replies are listed 'Best First'.
(jeffa) Re: Copying multi-level hash by jeffa (Bishop) on Mar 08, 2001 at 03:53 UTC
This worked just fine for me: `my %new = %{$hash{key1}{1}};` [download] it produced: `$VAR1 = 'var'; $VAR2 = 1; $VAR3 = 1; $VAR4 = { 'name1' => 'value3', 'name2' => 'value2', 'name3' => 'value3' };` [download] the extra '1' key is there because I was lazy and just eval'ed your Dumper output without 'use strict' . . . . short answer, take a number 2 :) Jeff R-R-R--R-R-R--R-R-R--R-R-R--R-R-R-- L-L--L-L--L-L--L-L--L-L--L-L--L-L--	[reply] [d/l] [select]
Re: Copying multi-level hash by merlyn (Sage) on Mar 08, 2001 at 03:58 UTC
See my column on deep copying. -- Randal L. Schwartz, Perl hacker	[reply]
Re: Copying multi-level hash by mt2k (Hermit) on Mar 08, 2001 at 03:59 UTC
Oh, and also, now if I wanted to place the %copy hash back in the big one (just theoretically), how would I do that? `1. %hash{'key1'}{1} = %{$copy}; 2. %hash{'key1'}{1} = %copy; 3. $hash{'key1'}{1} = %copy; 4. %{$hash{'key1'}{1}} = %copy; 5. %{$hash{'key1'}{1}} = %{$copy};` [download] Though I somehow think none of those look right...	[reply] [d/l]
(jeffa) Re: Re: Copying multi-level hash by jeffa (Bishop) on Mar 08, 2001 at 04:05 UTC
#3 was close `$hash{key1}{1} = \%copy;` [download] Jeff R-R-R--R-R-R--R-R-R--R-R-R--R-R-R-- L-L--L-L--L-L--L-L--L-L--L-L--L-L--	[reply] [d/l]
Re: Re: Copying multi-level hash by arturo (Vicar) on Mar 08, 2001 at 04:05 UTC
Remember above all : a reference is a scalar value, so reference it as you would a string (e.g.) -- as long as you remember it's pointing to something, instead of containing the value you want. Since you want to set it to a hashref: So: `$hash{key1}{1} = \%copy;` [download] should do ya. Philosophy can be made out of anything. Or less -- Jerry A. Fodor	[reply] [d/l]
Re: Copying multi-level hash by mt2k (Hermit) on Mar 08, 2001 at 04:15 UTC
Crap, that's all wrong... I don't want to create a reference, I want to copy the hash section... Sorry if I wasn't very clear on that... I know to get rid of the backslash in that one place, but I have no idea what to do with the %{$hash} part	[reply]
Re: Re: Copying multi-level hash by dvergin (Monsignor) on Mar 08, 2001 at 06:17 UTC
Give the way you get: `;-)` `%temp = %{$hash{key1}{1}}; then later: %{$hash{key1}{1}} = %temp;` [download]	[reply] [d/l] [select]


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