Re^2: while loop question

Thanks for the quick answer. nr.1 - copy-paste error. nr.2 - 100% RIGHT. nr.3 - understand. nr.4 - fast writing error :-) Sorry, code nr.4 is not good for "since you want to exit the loop when a certain key is reached" because I want to create a hash element if the has key is not there. For now I use the "defined" function (below) to do the work but I realy want to know if there is other solution.

unless ( defined $email{"email"} ) {
    $email{$html->param("email")}=$html->param("name");
}
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Re^3: while loop question by aitap (Curate) on Aug 21, 2014 at 11:48 UTC
exists should help you with this problem. As you may have noticed, looping over keys of a hash is much slower than accessing it by key. By the way, very often it is plain wrong.	[reply]
Re^4: while loop question by adriang (Sexton) on Aug 21, 2014 at 11:54 UTC
"exisys" is not good for me at leat for this crrent problem because I use AnyDBM_File: `AnyDBM_File doesn't define an EXISTS method at /gd/Development/Perl/Pr +actice/www/cgi-bin/submitcoffee.pl line 32.` [download]	[reply] [d/l]
Re^5: while loop question by SuicideJunkie (Vicar) on Aug 21, 2014 at 14:15 UTC
"EXISTS", "exisys" and "exists" are all different words. `exists` is not a method. It is a basic built-in perl function. It is completely and utterly unrelated to AnyDBM_File. It tells you if a key exists in a hash; that is what you want, no need for looping. Read the documentation linked by aitap for details.	[reply] [d/l]
Re^5: while loop question by aitap (Curate) on Aug 21, 2014 at 17:47 UTC
I can reproduce this error message: when I tie a hash using AnyDBM_File, it selects NDBM_File, which implements Tie::Hash without a `sub EXISTS { ... }`, so exists on the tied hash does not work. However, defined replaces exists in this case, because NDBM_File cannot store an undef in the database: #!/usr/bin/perl use Data::Dumper; use Fcntl; use AnyDBM_File; die $! unless tie %h, 'AnyDBM_File', 'test.db', O_RDWR()\|O_CREAT(), 06 +00; undef $h{'b'}; # try to store an undef print Dumper(\%h); # empty string is stored instead print "still defined\n" if defined $h{'b'}; # we can confirm its existence: # if it's defined, it does exist # and no undefs exist there delete $h{'b'}; # delete works as expected print "does not exist\n" unless defined $h{'b'}; print Dumper(\%h); __END__ $VAR1 = { 'b' => '' }; still defined does not exist $VAR1 = {}; [download] So using defined turns out to be the right decision.	[reply] [d/l] [select]