Re: Hash assignments using map

In addition to what others have said, you could do:

my @to_keep = (...);
my %keepers;
@keepers{@to_keep} = ();
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which you would then test with exists $keepers{$x}. Althought I'm curious why you need the %keepers hash if you have the @to_keep array.

Jeff japhy Pinyan, P.L., P.M., P.O.D, X.S.: Perl, regex, and perl hacker
How can we ever be the sold short or the cheated, we who for every service have long ago been overpaid? ~~ Meister Eckhart

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Re^2: Hash assignments using map by njcodewarrior (Pilgrim) on Feb 25, 2007 at 02:52 UTC
Hi japhy Not to beat a dead horse here, but to answer your question: I'm checking the keys in another hash against those in `%keepers`. If a keys exists in this other hash, but NOT in `%keepers`, I want to eliminate it from the hash. See this node for further explanation. Anyways, thanks for the clarification njcodewarrior	[reply] [d/l] [select]
Re^3: Hash assignments using map by japhy (Canon) on Feb 25, 2007 at 14:03 UTC
Right. My point is, why not loop over the elements in `@keepers`, rather than the keys of the other hash? `my %big_hash = (...); my @to_keep = ('abc', 'xyz'); %big_hash = map { exists($big_hash{$_}) ? ($_ => $big_hash{$_}) : () } + @to_keep; # or %big_hash = map { $_ => $big_hash{$_} } grep { exists $big_hash{$_} } +@to_keep;` [download] Jeff `japhy` Pinyan, P.L., P.M., P.O.D, X.S.: Perl, regex, and `perl` hacker How can we ever be the sold short or the cheated, we who for every service have long ago been overpaid? ~~ Meister Eckhart	[reply] [d/l] [select]