How can I sort many arrays according to one array?
I have a data structure like the following
@colors = qw(red blond green);
@numbers = qw(349 1234.5678 3.14159265);
@hats = qw(fedora porkpie bowler);
my %hash = (colors => \@colors, numbers => \@numbe开发者_JAVA百科rs, hats => \@hats);
I want to sort this according to the values of one of the arrays, maintaining the association of parallel array elements. That is, if I exchange $hash{numbers}[2]
and index $hash{numbers}[3]
, i want to do the same exchange for all the other arrays in the hash. In this case, if I sort {$a <=> $b}
on numbers
:
$sorted{numbers} = [3.14159265, 349, 1234.5678];
$sorted{colors} = ["green", "red", "blond"];
$sorted{hats} = ["bowler", "fedora", "porkpie"];
The solution i'm using now inverts the structure of %hash
into an array where $array[$i]{$k} == $hash{$k}[$i]
, does @sorted = sort {$a->{numbers} <=> $b->{numbers}} @array
, then converts @sorted
back from array of hashes to hash of arrays.
I don't really care if the sort is stable, I just wonder if there's a better way to do it.
Here's a trick I've used.
my @permutation = sort { $numbers[$a] <=> $numbers[$b] } (0..$#numbers);
@colors = @colors[@permutation];
@numbers = @numbers[@permutation];
@hats = @hats[@permutation];
# No change to %hash needed, since it has references to above arrays.
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