in reply to How I learned to stop worrying and love the hash slice. (boo)
in thread beyond me

I frequently use hash slices to eliminate duplicates from an array.

A simplified example: 

my @a = (1,2,3,2,1);
my %a;
@a{@a} = (1) x @a;
my @unique_a = keys %a;

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Of course, this does not preserve the order of the elements as they were in original array @a.

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Re: Re: How I learned to stop worrying and love the hash slice. (boo)
by blakem (Monsignor) on Aug 14, 2001 at 14:24 UTC
    Perhaps grep might work better here? 
    my @a = (1,2,3,2,1);
my %seen;
my @unique_a = grep {!$seen{$_}++} @a;

print "A:      $_\n" for (@a);
print "Unique: $_\n" for (@unique_a);

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    Assuming you wanted to keep the first occurance, this will preserve the original order.

    Or you can use map to create your %a hash. 

    my @a = (1,2,3,2,1);
my %a = map {$_=>1} @a;
my @unique_a = keys %a;

print "A:      $_\n" for (@a);
print "Unique: $_\n" for (@unique_a);

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    -Blake

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