Re^2: Using Tie::IxHash to keep database query keys/values in order

in reply to Re: Using Tie::IxHash to keep database query keys/values in order
in thread Using Tie::IxHash to keep database query keys/values in order

So Data::Dumper is throwing me off and Tie::IxHash just might be keeping them in order as advertised. I'll write a loop to check that. Thanks for the lesson in D::D

—Brad
"The important work of moving the world forward does not wait to be done by perfect men." George Eliot

Comment on Re^2: Using Tie::IxHash to keep database query keys/values in order

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Re^3: Using Tie::IxHash to keep database query keys/values in order by AnomalousMonk (Archbishop) on Feb 16, 2017 at 00:52 UTC
So Data::Dumper is throwing me off and Tie::IxHash just might be keeping them in order as advertised. It's unlikely that Data::Dumper has anything to do with it. As others have written, my guess would be that `selectall_arrayref()` is returning a reference to an entirely separate hash it generates and populates internally. After all, how would this function "know" that you want it to use the hash referred to by `$data` to populate with the data it is to return? I can't use Tie::IxHash to produce an example ATM, but consider: `c:\@Work\Perl\monks>perl -wMstrict -le "package Foo::Bar { sub TIEHASH {} } ;; my $data = {}; tie %$data, 'Foo::Bar'; print $data; ;; $data = return_anon_hash_ref(); print $data; ;; use Data::Dumper; print Dumper $data; ;; sub return_anon_hash_ref { return { 'sorry' => 'charley' }; } " HASH(0x3bd06c) HASH(0x3bd15c) $VAR1 = { 'sorry' => 'charley' };` [download] Note that the addresses of `$data` in the two print statements are different, as are the contents of the referents. Nothing you do with `Data::Dumper` is going to change this. Bottom line: Write your own data display loop or routine and use whatever explicit key order you want. Give a man a fish: `<%-{-{-{-<`	[reply] [d/l] [select]

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Re^3: Using Tie::IxHash to keep database query keys/values in order
by AnomalousMonk (Archbishop) on Feb 16, 2017 at 00:52 UTC

So Data::Dumper is throwing me off and Tie::IxHash just might be keeping them in order as advertised.

It's unlikely that Data::Dumper has anything to do with it. As others have written, my guess would be that selectall_arrayref() is returning a reference to an entirely separate hash it generates and populates internally. After all, how would this function "know" that you want it to use the hash referred to by $data to populate with the data it is to return? I can't use Tie::IxHash to produce an example ATM, but consider:

c:\@Work\Perl\monks>perl -wMstrict -le
"package Foo::Bar { sub TIEHASH {} }
 ;;
 my $data = {};
 tie %$data, 'Foo::Bar';
 print $data;
 ;;
 $data = return_anon_hash_ref();
 print $data;
 ;;
 use Data::Dumper;
 print Dumper $data;
 ;;
 sub return_anon_hash_ref { return { 'sorry' => 'charley' }; }
"
HASH(0x3bd06c)
HASH(0x3bd15c)
$VAR1 = {
          'sorry' => 'charley'
        };
[download]

$data

Data::Dumper

Bottom line: Write your own data display loop or routine and use whatever explicit key order you want.

Give a man a fish: <%-{-{-{-<

[reply]
[d/l]
[select]

In Section Seekers of Perl Wisdom