in reply to Why does this hash remove duplicate lines

an interesting technique but all it amounts to is testing for the existence of a hash element, which can also be done (perhaps more intuitively) thus:

my %lines;

while (<DATA>) {
        unless (exists($lines{$_})) {print "$_"}
        $hash{$_}="done";   # element defined
}

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Re^2: Why does this hash remove duplicate lines
by olus (Curate) on Mar 06, 2008 at 11:38 UTC

    Nice try, but you should have tested it? %lines and %hash are two different hashes :). strict and warnings would have told you that.

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