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Re: Converting HoA into AoH

by BrowserUk (Pope)
on Oct 31, 2005 at 09:13 UTC ( #504195=note: print w/replies, xml ) Need Help??


in reply to Converting HoA into AoH

I think this does it? And should handle your real data without problems.

Updated: see comment for the one-line change.

#! perl -slw use strict; use Data::Dumper; sub combs { my @inputs = @_; my @saved = my @index = map{ scalar $#$_ } @inputs; my $next = $#index; return sub{ if( $index[ 0 ] == -1 ) { @index = @saved; return (); } my $rv = [ map{ $inputs[ $_ ][ $index[ $_ ] ] } 0 .. $#inputs +]; if( $index[ $next ] ) { $index[ $next ]--; } else { $next-- until $index[ $next ] or $next == 0; $index[ $next++ ]--; @index[ $next .. $#index ] = @saved[ $next .. $#index ]; $next = $#index; } return $rv; } } sub Cnr{ my $n = shift; return [] unless $n--; map{ my $x = $_; map{ [ $_[$x], @$_ ] } Cnr( $n, @_[ ($x + 1) .. $#_ ] ); } 0 .. ($#_ - $n); } my $HoA = { flintstones => [ "fred", "barney" ], jetsons => [ "george", "jane"], domo => [ "harry", "gato" ], }; my $AoH = [ map { my @array; my $iter = combs @{ $HoA }{ @$_ }; while( my $vals = $iter->() ) { my %hash; @hash{ @$_ } = @$vals; push @array, \%hash; } @array; } Cnr scalar keys %{ $HoA }, keys %{ $HoA } ## } Cnr 2, keys %{ $HoA } ##Replaced ]; print Dumper $AoH; __END__ P:\test>504165 $VAR1 = [ { 'flintstones' => 'barney', 'jetsons' => 'jane', 'domo' => 'gato' }, { 'flintstones' => 'barney', 'jetsons' => 'jane', 'domo' => 'harry' }, { 'flintstones' => 'fred', 'jetsons' => 'jane', 'domo' => 'gato' }, { 'flintstones' => 'fred', 'jetsons' => 'jane', 'domo' => 'harry' }, { 'flintstones' => 'barney', 'jetsons' => 'george', 'domo' => 'gato' }, { 'flintstones' => 'barney', 'jetsons' => 'george', 'domo' => 'harry' }, { 'flintstones' => 'fred', 'jetsons' => 'george', 'domo' => 'gato' }, { 'flintstones' => 'fred', 'jetsons' => 'george', 'domo' => 'harry' } ];

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Re^2: Converting HoA into AoH
by neversaint (Deacon) on Oct 31, 2005 at 10:19 UTC
    Dear BrowserUk,
    Thanks so much BrowserUk. But with your dataset example above it should give this result instead: So the size of individual size of hash must be the same with initial size of HoA.

    ---
    neversaint and everlastingly indebted.......

      There were two possibilities for the extended example, and I chose the wrong one (again).

      But it's only a one line change, to pass the number of keys in the hash rather than the constant 2-- assuming I understood this time?


      Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
      Lingua non convalesco, consenesco et abolesco. -- Rule 1 has a caveat! -- Who broke the cabal?
      "Science is about questioning the status quo. Questioning authority".
      In the absence of evidence, opinion is indistinguishable from prejudice.

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