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Get the Key corresponding to any given value

by rmalhotra (Initiate)
on Jun 28, 2002 at 09:11 UTC ( #177969=categorized question: print w/replies, xml ) Need Help??
Contributed by rmalhotra on Jun 28, 2002 at 09:11 UTC
Q&A  > hashes


Description:

Is there any way to get the key corresponding to a given value from a hash table

Answer: Get the Key corresponding to any given value
contributed by jsprat

If the values are unique:

my %rhash = reverse %hash; my $key = $rhash{$value};

will give you the key for a given value.

If you might have duplicate values, grep is your friend:

my @keys = grep { $hash{$_} eq $value } keys %hash;

If your values are numeric, use "==" instead of eq.
Answer: Get the Key corresponding to any given value
contributed by manav

Most of these cases have been covered in the perlfaq itself. See How do I look up a hash element by value?

Answer: Get the Key corresponding to any given value
contributed by simmisam

my ($key) = grep {$value ~~ $hash{$_}} keys %hash; print "Key = $key\n";

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