List::Util is core and also exports uniq.

use List::Util qw( uniq );
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Or, write your own:

sub uniq {
    my @values = @_;
    my %uniq;
    @uniq{@values} = ();
    return keys %uniq
}
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or, if you want to keep the order:

sub uniq {
    my @values = @_;
    my %seen;
    return grep ! $seen{$_}++, @values
}
[download]