Re: Check/set hash of hashes value

Thanks people - that did the trick ! I've tested out both and they work. But perhaps for me, this is more obvious and will make it easier for me to work out exactly what I'm doing here, should I need to look back on it:

foreach my $ip ( keys %subnets ) {
    $subnets{$ip}{comment} //= 'ALLOCATED';
}
[download]

Thanks again

Comment on Re: Check/set hash of hashes value Download Code

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Re^2: Check/set hash of hashes value by sammy_01 (Initiate) on Jun 25, 2013 at 05:43 UTC
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"; }` [download]	[reply] [d/l]
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]