I can think of two ways to accomplish this. Either might be appropriate, depending upon what you want to do. The second method is probably cleaner if you can assemble the entire hash at once and do a single reversal on it.

#!/usr/bin/perl -w
use strict;

my %hash = qw(
    foo 1
    bar 1
    baz 1
);

my $ref = \$hash{bar};

my ($key) = grep { \$hash{$_} eq $ref } keys %hash;
print "$key\n";

# or

my %ref_hash = map { \$hash{$_}, $_ } keys %hash;
print $ref_hash{$ref};
[download]

With either of these solutions, though, I suspect that you likely have a design issue. Can you step back and explain the larger problem? We can probably come up with a better way of accomplishing what you need.

Cheers,
Ovid

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