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Re: Checking if hash value exists without implicitly defining it

by Ratazong (Monsignor)
on Feb 14, 2013 at 15:52 UTC ( #1018749=note: print w/replies, xml ) Need Help??

in reply to Checking if hash value exists without implicitly defining it

Hi Doctrin,

as others have pointed out, you are suffering from autovivification. In order to avoid autovivification in your specific case, you could also check each level of the hash for existence before dereferencing it (and therefore before autovivification is triggered). The code could look like this:

if (exists $Hash{$neededVal} && exists $Hash{$neededVal}{param1} && ex +ists $Hash{$neededVal}{param1}{key1}) { print "DEFINED\n"; }
It takes advantage of the fact that the && s inside the condition are evaluated from left to right, and the evaluation is aborted once a "false" occurs.

HTH, Rata

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