in reply to Re: Sorting Index of An Array
in thread Sorting Index of An Array

Use a Schwartzian transform

To sort lists of nine elements, applying the ST is probably counterproductive. And anyway, for that particular problem, using a Orcish Maneuver would be more suitable: 

my @index_sorted = map {
  my @row = splice @sim, 0, N;
  sort { $row[$b] <=> $row[$a] } 0..(N-1);
} 0..(M-1);

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Re^3: Sorting Index of An Array
by shmem (Chancellor) on May 14, 2007 at 13:18 UTC
    Just a nit - while your approach is far better than mine and less convoluted, there's no OR and no cache, so there's no Orcish (or-cache) Maneuver. That would be (from Shlomo Yona's Perl lectures 2002):

    The Orcish Maneuver -- example

    keys my %or_cache = @in;
@out = sort {
    ($or_cache{$a} ||= KEY($a))
    cmp
    ($or_cache{$b} ||= KEY($b))
} @in;

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    The first part of the sortsub sees if the sortkey for $a is cached.

    If not, it extracts the value of the sortkey from the operand and caches it.

    The sortkey for $a is then compared to the sortkey for $b.

    Anyways, salva++ for simplifying things :-)

    --shmem 

    _($_=" "x(1<<5)."?\n".q·/)Oo.  G°\        /
                              /\_¯/(q    /
----------------------------  \__(m.====·.(_("always off the crowd"))."·
");sub _{s./.($e="'Itrs `mnsgdq Gdbj O`qkdq")=~y/"-y/#-z/;$e.e && print}
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