in reply to Re^3: best sort
in thread best sort

If those were the things I was looking into, I would certainly not want a bare sort for any of them.

If you anticipate repeated elements, you'd probably want a tie-breaking 

$a cmp $b

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(the bare sort comparison function) on all but the first, because non-identical terms can otherwise compare equal and identical elements may not be adjacent in the sorted output. But I think we are in fundamental agreement: You need to know what you are comparing and how. That may be easier said than done. Knowing that "machenry" is a Scottish name, but "machinery" is not (or is it, and, if not, why not) makes "knowing what you are comparing" non-trivial.

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Re^5: best sort
by tchrist (Pilgrim) on Aug 16, 2011 at 17:30 UTC
    If those were the things I was looking into, I would certainly not want a bare sort for any of them.
    If you anticipate repeated elements, you'd probably want a tie-breaking 
    $a cmp $b

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    Well, sure. Here’s some of the code to generate one of those: 
    say $_->{PHRASE} for sort {
    $b->{TOTAL_VOWELS} <=>  $a->{TOTAL_VOWELS}
                        ||
   $b->{MAX_ANY_VOWEL} <=>  $a->{MAX_ANY_VOWEL}
                        ||
        $b->{NUM_OF_A} <=>  $a->{NUM_OF_A}
                        ||
        $b->{NUM_OF_E} <=>  $a->{NUM_OF_E}
                        ||
        $b->{NUM_OF_I} <=>  $a->{NUM_OF_I}
                        ||
        $b->{NUM_OF_O} <=>  $a->{NUM_OF_O}
                        ||
        $b->{NUM_OF_U} <=>  $a->{NUM_OF_U}
                        ||
        $b->{NUM_OF_Y} <=>  $a->{NUM_OF_Y}
                        ||
        $a->{DICTFOLD} cmp  $b->{DICTFOLD};
                        ||
           $a->{RECNO} <=>  $b->{RECNO};
} @records;

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    Look more reasonable?
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      It helps a lot with the how I am comparing part, although if anyone guessed in advance that was how By vowels: sorted, I'd like to solicit their advice on the outcome of upcoming NFL games. It's still not exactly what I had in mind for bringing all identical terms together. The 
      $a->{RECNO} <=>  $b->{RECNO}

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      is unnecessary if the sort is stable, as sort() is, by default. Since different words can compare equal under the influence of 
      $a->{DICTFOLD} cmp  $b->{DICTFOLD}

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      (if I'm correctly guessing what DICTFOLD is), I still might see 
      word
Word
word
Word

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      in the sorted output, when I might have preferred 
      word
word
Word
Word

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      which makes it easier to determine if words are "unique" without repeating all the complicated logic. So I would prefer 
      $a->{ORIGINAL} cmp $b->{ORIGINAL}

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      as the final tie-breaker. That's neither better nor worse than your code, merely different.
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