Re: Converting HoA into AoH

[Zaxo]

This is my previous function rewritten to handle spaces in the data by escaping them. Other surprises may be handled similarly.

#!/usr/bin/perl

use Data::Dumper;

sub hoa2aoh {
    my $hoa = shift;
    my @keys = keys %$hoa;
    my @patterns = map {
        local $" = ',';
        "{@{[map {s/ /\\ /g; $_} @$_]}}";
    } values %$hoa;
    [
        map {
            my %hash;
            @hash{@keys} = split ',';
            \%hash;
        } glob join ',', @patterns
    ];
}

my $HoA = {
    '1,2,flintstones' => [ 'fred-1 foo-2', 'barney-1 bar-2' ],
    '2,3,jetsons'   => [ 'george-1 foo-2', 'jane-1 bar-2'],
};

print Dumper hoa2aoh($HoA);

__END__

$VAR1 = [
          {
            '1,2,flintstones' => 'fred-1 foo-2',
            '2,3,jetsons' => 'george-1 foo-2'
          },
          {
            '1,2,flintstones' => 'barney-1 bar-2',
            '2,3,jetsons' => 'george-1 foo-2'
          },
          {
            '1,2,flintstones' => 'fred-1 foo-2',
            '2,3,jetsons' => 'jane-1 bar-2'
          },
          {
            '1,2,flintstones' => 'barney-1 bar-2',
            '2,3,jetsons' => 'jane-1 bar-2'
          }
        ];

[robin]

Using glob is a delightful trick, but in general you really need to escape the string much more than this. (To see what I mean, try putting a * in one of the strings.)

Instead of s/ /\\ /g, use s/(\W)/\\\\\\$1/g. I know it’s a lot of backslashes, but you really do need that many here!