On Oct 31, 2005, at 9:56, Gundala Viswanath wrote:
Here is the example, given this HoA:
my $HoA = {
'flintstones' => [ "fred-1 foo-2", "barney-1 bar-2" ],
'jetsons' => [ "george-1 foo-2", "jane-1 bar-2"],
};
How can I convert them to an AoH
my $AoH = [ # Desired results.
{
'flinstones' => "fred-1 foo-2",
'jetsons' => "george-1 foo-2"
},
{
'flinstones' => "fred-1 foo-2",
'jetsons' => "jane-1 bar-2"
},
{
'flinstones' => "barney-1 bar-2",
'jetsons' => "george-1 foo-2"
},
{
'flinstones' => "barney-1 bar-2",
'jetsons' => "jane-1 bar-2"
},
];
Looks like you want all the possible permutations of the values
(within each key). If that's right this is a possible solution. I
wrote this code based on iterators (inspired by HOP), in case the
structure is not small:
use strict;
use warnings;
use Data::Dumper;
my $HoA = {
'flintstones' => [ "fred-1 foo-2", "barney-1 bar-2" ],
'jetsons' => [ "george-1 foo-2", "jane-1 bar-2"],
};
print Dumper(HoA_to_AoH($HoA));
sub HoA_to_AoH {
my ($HoA) = @_;
my @keys = keys %{$HoA};
return [] if not @keys;
my @AoH = ();
my $nkeys = @keys;
my $nvals = @{$HoA->{$keys[0]}};
my $iter = indexes($nvals, $nkeys);
while (my $idxs = $iter->()) {
my %H = ();
my $i = 0;
for my $k (@keys) {
$H{$k} = $HoA->{$k}[$i];
++$i;
}
push @AoH, \%H;
}
return [EMAIL PROTECTED];
}
# Returns an iterator that generates all permutations with
# repetitions of numbers from 0 to $n-1 in blocks of $k.
#
# Permutations are generated as arrayrefs, and undef is returned
# when the iterator is exhausted.
sub indexes {
my ($n, $k) = @_;
my $max_i = $n-1;
my @idxs = (-1, (0) x ($k-1));
return sub {
my $exhausted = 1;
IDXS:
for my $i (@idxs) {
if ($i < $max_i) {
++$i;
$exhausted = 0;
last IDXS;
}
$i = 0;
}
return $exhausted ? undef : [ @idxs ];
};
}
-- fxn
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