Hash error

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

Hi monks i want to print hash keys and values without changing the order what can i do for that for example

#!/usr/bin/perl
#hash2.plx
use warnings;
use strict;
my %where=(
Gary => "Dallas",
Lucy => "Exeter",
Ian => "Reading",
Samantha => "Oregon"
);
for (keys %where) {
print "$_ lives in $where{$_}\n";
}
_OUTPUT_
Samantha lives in Oregon
Gary lives in Dallas
Lucy lives in Exeter
Ian lives in Reading
_EXPECTED OUTPUT_
Gary lives in Dallas
Lucy lives in Exeter
Ian lives in Reading
Samantha lives in Oregon
[download]

that means i want to print the keys and values without changing the order

Comment on Hash error Download Code

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Re: Hash error by toolic (Bishop) on Apr 20, 2010 at 17:57 UTC
Use Tie::IxHash `use strict; use warnings; use Tie::IxHash; tie my %where, 'Tie::IxHash'; %where = ( Gary => "Dallas", Lucy => "Exeter", Ian => "Reading", Samantha => "Oregon" ); for ( keys %where ) { print "$_ lives in $where{$_}\n"; }` [download] This is a FAQ: `perldoc -q hash` [download] How can I make my hash remember the order I put elements into it? To neaten up your code, see perltidy	[reply] [d/l] [select]
Re: Hash error by ikegami (Patriarch) on Apr 20, 2010 at 17:55 UTC
`use warnings; use strict; my @where = ( [ Gary => "Dallas" ], [ Lucy => "Exeter" ], [ Ian => "Reading" ], [ Samantha => "Oregon" ], ); for (@where) { print "$_->[0] lives in $_->[1]\n"; }` [download]	[reply] [d/l]
Re: Hash error by almut (Canon) on Apr 20, 2010 at 17:54 UTC
See Tie::IxHash	[reply]
Re: Hash error by AR (Friar) on Apr 20, 2010 at 18:03 UTC
The above monks gave you solutions to what you asked for. I'm going to speak briefly on why it doesn't work the way you are expecting. Hashes in Perl are not meant to maintain the order in which they are built. We already have arrays for that specific reason. When you access the keys of the hash, they are returned in an order which is related to the hashing function applied to the key. When you choose to use a hash, it's assumed you are not going to want to access the entries by any means other than the keys. If you want to do so, you'll need something more complicated, like what the above monks suggest.	[reply]
Re: Hash error by Old_Gray_Bear (Bishop) on Apr 20, 2010 at 20:19 UTC
You do realize that a Hash Table has its own idea of the order of the keys? If key order is really important to you, then you need to either use a module that keeps track of the order under the covers; sort the keys into the 'proper order' and then retrieve the values based on the sorted-key; or accept the fact that Hash order is in neither time-sequence nor alphabetical-order. ---- I Go Back to Sleep, Now. OGB	[reply]