It needs a real hash to work on (possibly there is a more technical description of this), but the map just produces a list of values, not a hash.

You can do it all in one line though:

use 5.010;
sub uniq {
    return keys %{ {map { $_ => 1 } @_} };
}

say for uniq qw/ foo bar foo baz bip foo /;

[download]

Good Day,
    Dean

In reply to Re: Why does 'keys' need a named hash? by duelafn
in thread Why does ‘keys’ need a named hash? by ankitpati

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