Re^2: Check/set hash of hashes value

You can use this way as well..

foreach $ip (keys(%subnets)) {
  if("$subnets{$ip}{'comment'}" eq "") {
      $subnets{$ip}{'comment'} = "ALLOCATED";
  }
  print "$subnets{$ip}{'comment'}\n";
}
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Re^3: Check/set hash of hashes value by kennethk (Abbot) on Jun 25, 2013 at 15:47 UTC
If you are testing if a value is defined, you should test that. It is possible (not knowing this person's dataset) that empty string is a legitimate value. exists, defined and eq are different for a reason. If you use warnings, Perl will emit a warning every time you compare with an undefined value; it's a helpful tool to figure out if you've forgotten to initialize a variable. With your code and warnings, there would be a large amount of unnecessary noise on STDERR. #11929 First ask yourself `How would I do this without a computer?' Then have the computer do it the same way.	[reply]

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Re^3: Check/set hash of hashes value
by kennethk (Abbot) on Jun 25, 2013 at 15:47 UTC

exists

defined

If you use warnings, Perl will emit a warning every time you compare with an undefined value; it's a helpful tool to figure out if you've forgotten to initialize a variable. With your code and warnings, there would be a large amount of unnecessary noise on STDERR.

#11929 First ask yourself `How would I do this without a computer?' Then have the computer do it the same way.

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