Re: "print" of nonexistent element is actually altering a hash

Replies are listed 'Best First'.
Re^2: "print" of nonexistent element is actually altering a hash by bliako (Abbot) on Feb 18, 2020 at 07:47 UTC
right, but be careful because AnomalousMonk warned that `exists()` will autovivify in some cases. Perhaps you want to run your program with and without `no autovivification;` and diff your resultant data structure.	[reply] [d/l] [select]
Re^2: "print" of nonexistent element is actually altering a hash by Anonymous Monk on Feb 18, 2020 at 00:18 UTC
Hi `use Data::Diver qw/ Dive /; print Dive( \%hash, qw/ key0 key1 key2 /); ## doesn't alter %hash` [download]	[reply] [d/l]
Re^2: "print" of nonexistent element is actually altering a hash by Anonymous Monk on Feb 18, 2020 at 02:07 UTC
Yes, as other "Anonymous Monks" have said – a feature. Because, if you are legitimately trying to use something like `$hash{'www'}{'xxx'}{'yyy'}{'zzz'}`, it is "hugely convenient" that Perl will automagically create `$hash{'www'}` then `$hash{'www'}{'xxx'}` then `$hash{'www'}{'xxx'}{'yyy'}`, and maybe even `$hash{'www'}{'xxx'}{'yyy'}{'zzz'}`, all without asking. This very simple trick bypasses a lot of tedium and is "usually" beneficial. Just not in your case!	[reply]
Re^3: "print" of nonexistent element is actually altering a hash by Anonymous Monk on Feb 18, 2020 at 16:18 UTC
Mike, you do realize you could save yourself the time and hassle of posting here and both the OP and PerlMonks would be just as well off. Don't you?	[reply]