Adding values from an array to a hash

PerlingTheUK has asked for the wisdom of the Perl Monks concerning the following question:

Dear Monks, I have just found a bug where a code was:

%locations = map{ $_ => 1 } ( @locations );
[download]

but should have done

%locations = map{ $_ => 1 } ( @locations, keys %locations );
[download]

Now I think that this setup is really annoying, easpecially as I would like rewrite it so that every value is counted to represent how often a location has been added. Is there a way to add onto the old hash instead of completely rewriting it?

Cheers,
PerlingTheUK

Comment on Adding values from an array to a hash Select or Download Code

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Re: Adding values from an array to a hash by davorg (Chancellor) on Oct 12, 2006 at 10:10 UTC
Do you mean this: `$locations{$_}++ for @locations;` [download] -- <http://dave.org.uk> "The first rule of Perl club is you do not talk about Perl club." -- Chip Salzenberg	[reply] [d/l]
Re: Adding values from an array to a hash by blazar (Canon) on Oct 12, 2006 at 10:29 UTC
Now I think that this setup is really annoying, easpecially as I would like rewrite it so that every value is counted to represent how often a location has been added. Is there a way to add onto the old hash instead of completely rewriting it? I'm not really sure if I understand your question, but you probably either want `%locations=(%locations, map {$_ => 1} @locations);` [download] or `$locations{$_}++ for @locations;` [download]	[reply] [d/l] [select]
Re: Adding values from an array to a hash by reneeb (Chaplain) on Oct 12, 2006 at 11:27 UTC
You can do this: `@locations{@locations} = (1) x scalar @locations`	[reply] [d/l]