Re: How do I write my own sorting routine?

If you have a hash which specifies an ordering for values, then your sorting is much easier:

my %hash = (
  "very slow"  => 1,
  "slow"       => 2,
  "slowish"    => 3,
  "medium"     => 4,
  "acceptable" => 5,
  "fast"       => 6,
  "very fast"  => 7,
);
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Now to sort, we just compare the array elements as keys into the hash:

my @sorted = sort { $hash{$a} <=> $hash{$b} } @array;
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Hence:

my @array = ("slow", "very fast", "fast", "very slow", "acceptable");
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would sort into:

very slow, slow, acceptable, fast, very fast
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Re: Answer: How do I write my own sorting routine? by Roger (Parson) on Dec 22, 2003 at 12:44 UTC
I believe the correct sorting should be `my @sorted = sort { $hash{$a} <=> $hash{$b} } @array;` [download] Note the use of the 'spaceship' comparison operator instead of the cmp operator. The reason is that cmp compares the values based on string values, while <=> compares the values based on numerical values. So if your hash has values 1 to 10, the ordering with cmp produces 1,10,2,3,..., while ordering with <=> produces 1,2,3....,10.	[reply] [d/l]

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Re: Answer: How do I write my own sorting routine?
by Roger (Parson) on Dec 22, 2003 at 12:44 UTC

my @sorted = sort { $hash{$a} <=> $hash{$b} } @array;
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[reply]
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