Re: Hash Key function puzzlement -- a point of information query
keys is a function, it doesn't take in value On Thu, May 3, 2012 at 9:08 AM, Rothenmaier, Deane deane.rothenma...@walgreens.com wrote: Gurus, Given something like this: #!Perl use strict; use warnings; my %hash; keys(%hash) = 128; print “hash has “ . scalar(keys(%hash)) . “ keys\n”; I should see a printed value of 128, wouldn’t you think? But no, it prints: “hash has 0 keys”. What’s up wit dat? What obvious thing am I missing? Thanks, Deane Rothenmaier Programmer/Analyst – IT-StdCfg Walgreens Corp. 2 Overlook Point #N51022D MS 6515 Lincolnshire, IL 60069 224-542-5150 The more corrupt the republic, the more numerous the laws. -- Tacitus ___ Perl-Win32-Users mailing list Perl-Win32-Users@listserv.ActiveState.com To unsubscribe: http://listserv.ActiveState.com/mailman/mysubs ___ Perl-Win32-Users mailing list Perl-Win32-Users@listserv.ActiveState.com To unsubscribe: http://listserv.ActiveState.com/mailman/mysubs
Re: Hash Key function puzzlement -- a point of information query
What Leo said. keys(%hash) returns the keys from the hash as an array, you can't assign to it AFAIK. On Thu, May 3, 2012 at 10:18 AM, Leo Susanto leosusa...@gmail.com wrote: keys is a function, it doesn't take in value On Thu, May 3, 2012 at 9:08 AM, Rothenmaier, Deane deane.rothenma...@walgreens.com wrote: Gurus, Given something like this: #!Perl use strict; use warnings; my %hash; keys(%hash) = 128; print “hash has “ . scalar(keys(%hash)) . “ keys\n”; I should see a printed value of 128, wouldn’t you think? But no, it prints: “hash has 0 keys”. What’s up wit dat? What obvious thing am I missing? Thanks, Deane Rothenmaier Programmer/Analyst – IT-StdCfg Walgreens Corp. 2 Overlook Point #N51022D MS 6515 Lincolnshire, IL 60069 224-542-5150 The more corrupt the republic, the more numerous the laws. -- Tacitus ___ Perl-Win32-Users mailing list Perl-Win32-Users@listserv.ActiveState.com To unsubscribe: http://listserv.ActiveState.com/mailman/mysubs ___ Perl-Win32-Users mailing list Perl-Win32-Users@listserv.ActiveState.com To unsubscribe: http://listserv.ActiveState.com/mailman/mysubs ___ Perl-Win32-Users mailing list Perl-Win32-Users@listserv.ActiveState.com To unsubscribe: http://listserv.ActiveState.com/mailman/mysubs
RE: Hash Key function puzzlement -- a point of information query
Keys can be used as an lvalue. $ perldoc -f keys ... As an lvalue keys allows you to increase the number of hash buckets allocated for the given hash. This can gain you a measure of efficiency if you know the hash is going to get big. (This is similar to pre-extending an array by assigning a larger number to $#array.) If you say keys %hash = 200; ... That said, using it as an lvalue does not magically create random keys in the hash. It just gives the interpreter a hint on how much memory should be allocated for it. --Tobias -Original Message- From: perl-win32-users-boun...@listserv.activestate.com [mailto:perl- win32-users-boun...@listserv.activestate.com] On Behalf Of Aaron Hawryluk Sent: Thursday, May 03, 2012 10:23 AM To: Rothenmaier, Deane; perl-win32-users@listserv.ActiveState.com Subject: Re: Hash Key function puzzlement -- a point of information query What Leo said. keys(%hash) returns the keys from the hash as an array, you can't assign to it AFAIK. On Thu, May 3, 2012 at 10:18 AM, Leo Susanto leosusa...@gmail.com wrote: keys is a function, it doesn't take in value On Thu, May 3, 2012 at 9:08 AM, Rothenmaier, Deane deane.rothenma...@walgreens.com wrote: Gurus, Given something like this: #!Perl use strict; use warnings; my %hash; keys(%hash) = 128; print “hash has “ . scalar(keys(%hash)) . “ keys\n”; I should see a printed value of 128, wouldn’t you think? But no, it prints: “hash has 0 keys”. What’s up wit dat? What obvious thing am I missing? Thanks, Deane Rothenmaier Programmer/Analyst – IT-StdCfg Walgreens Corp. 2 Overlook Point #N51022D MS 6515 Lincolnshire, IL 60069 224-542-5150 The more corrupt the republic, the more numerous the laws. -- Tacitus ___ Perl-Win32-Users mailing list Perl-Win32-Users@listserv.ActiveState.com To unsubscribe: http://listserv.ActiveState.com/mailman/mysubs ___ Perl-Win32-Users mailing list Perl-Win32-Users@listserv.ActiveState.com To unsubscribe: http://listserv.ActiveState.com/mailman/mysubs ___ Perl-Win32-Users mailing list Perl-Win32-Users@listserv.ActiveState.com To unsubscribe: http://listserv.ActiveState.com/mailman/mysubs ___ Perl-Win32-Users mailing list Perl-Win32-Users@listserv.ActiveState.com To unsubscribe: http://listserv.ActiveState.com/mailman/mysubs
RE: Hash Key function puzzlement -- a point of information query
From: perl-win32-users-boun...@listserv.activestate.com [mailto:perl-win32-users-boun...@listserv.activestate.com] On Behalf Of Rothenmaier, Deane Sent: 03 May 2012 17:08 To: perl-win32-users@listserv.ActiveState.com Subject: Hash Key function puzzlement -- a point of information query Gurus, Given something like this: #!Perl use strict; use warnings; my %hash; keys(%hash) = 128; You have changed the number of hash buckets, not the number of keys. print hash has . scalar(keys(%hash)) . keys\n; I should see a printed value of 128, wouldn't you think? But no, it prints: hash has 0 keys. What's up wit dat? What obvious thing am I missing? That's correct, because you have not added any keys. HTH -- Brian Raven Please consider the environment before printing this e-mail. This e-mail may contain confidential and/or privileged information. If you are not the intended recipient or have received this e-mail in error, please advise the sender immediately by reply e-mail and delete this message and any attachments without retaining a copy. Any unauthorised copying, disclosure or distribution of the material in this e-mail is strictly forbidden. ___ Perl-Win32-Users mailing list Perl-Win32-Users@listserv.ActiveState.com To unsubscribe: http://listserv.ActiveState.com/mailman/mysubs
