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;

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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

In reply to Re^3: Hash assignments using map by japhy
in thread Hash assignments using map by njcodewarrior

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