Choosing %hash by scalar value

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

Hi there,

have this tiny but overly irritating issue where i would like to choose iterated %hash by scalar value. So if $choise variable contains string "computerAttributes", iterate through %computerAttributes. This way i can have only one foreach loop defined in the program, but several hashes to choose from. Must have a brain malfunction or something, but i just can't figure this one out.

#!/usr/bin/perl -w

use strict;

my $choice = 'computerAttributes';

my %computerAttributes = (

  cn => 'Common Name (eg. John Doe)',
  distinguishedName => 'Computer distinguishedname (dn) representing o
+bject location in LDAP-directory',
  lastLogOff => 'Last time LDAP-directory received logoff message from
+ system'
);

my %userAttributes = (

  cn => 'Common Name (eg. laptop1)',
  sn => 'Surename',
  displayName => 'First and lastname',
  title => ''
);

foreach (my $key = keys %($choice))
{
  print "$key\n";
}
[download]

Comment on Choosing %hash by scalar value Download Code

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Re: Choosing %hash by scalar value by NetWallah (Canon) on Feb 05, 2006 at 22:58 UTC
Here is another way - Ref to existing hash .. Move "choice" declaration down, and change last few lines to : `my $choice = \%computerAttributes; foreach my $key ( keys %{$choice}) { print "$key\n"; }` [download] Although this does not exactly map to your problem description (since $choice is NOT a string anymore), I suggest that this is a less error-prone approach, and you should structure your code to use this mechanism, if you possibly can. If not, the HOH solution described above is a good choice. "For every complex problem, there is a simple answer ... and it is wrong." --H.L. Mencken	[reply] [d/l]
Re^2: Choosing %hash by scalar value by mellin (Scribe) on Feb 05, 2006 at 23:27 UTC
Great! Using references is without a doubt the best way to achieve my goal. Thank you.	[reply]
Re: Choosing %hash by scalar value by tirwhan (Abbot) on Feb 05, 2006 at 22:46 UTC
Use a hash of hashes `my %attributes = ( computerAttributes => { cn => 'Common Name (eg. John Doe)', distinguishedName => 'Computer distinguishedname (dn) represen +ting object location in LDAP-directory', lastLogOff => 'Last time LDAP-directory received logoff + message from system' }, userAttributes => { cn => 'Common Name (eg. laptop1)', sn => 'Surename', displayName => 'First and lastname', title => '' } ) for my $key (keys %{$attributes{$choice}}) { print "Key: $key\tValue: $attributes{$choice}->{$key}\n"; }` [download] Update: showed how to print key-value pair, at ysth's suggestion. All dogma is stupid.	[reply] [d/l]