How to sort a AoH reference

bradcathey has asked for the wisdom of the Perl Monks concerning the following question:

Fellow Monasterians,

I have no problem sorting an AoH, but when I try to sort it as a reference (as I fetchall_arrayref it from MySQL for a HTML::Template loop) I get zero results. I've Googled and SS'ed with little success. Anyway, what am I missing? Thanks.

my $sqldata = [
   { level => 2, menuname => 'cccccc' },
   { level => 3, menuname => '333333' },   
   { level => 3, menuname => '222222' },
   { level => 1, menuname => 'CCCCCC' },
   { level => 2, menuname => 'bbbbbb' },
   { level => 1, menuname => 'BBBBBB' },
   { level => 1, menuname => 'AAAAAA' },
   { level => 3, menuname => '111111' },
   { level => 2, menuname => 'aaaaaa' },
];
      
my $sorted = sort { 

                  $a->{level} <=> $b->{level}
                                 || 
                  [$a->{menuname} cmp $b->{menuname}
                  
                  } @$sqldata;

for ( 0 .. $#$sorted ) {
   print $sorted->[$_]{level}." ".$sorted->[$_]{menuname}."<br>";
}
[download]

—Brad
"The important work of moving the world forward does not wait to be done by perfect men." George Eliot

Comment on How to sort a AoH reference Select or Download Code

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Re: How to sort a AoH reference by dragonchild (Archbishop) on Jun 01, 2005 at 14:38 UTC
`my $sorted = []; @$sorted = ...` [download] Sort returns an array, not an arrayreference. In general, if you think something isn't in Perl, try it out, because it usually is. :-) "What is the sound of Perl? Is it not the sound of a wall that people have stopped banging their heads against?"	[reply] [d/l]
Re: How to sort a AoH reference by Transient (Hermit) on Jun 01, 2005 at 14:41 UTC
That gives me: `Useless use of sort in scalar context at ./testsort.pl line 22.` [download] Changing the "my $sorted" to "my @sorted" (and the like changes below in the foreach loop) gives me sorted results. (and I assume the code is not cut-and-pasted, because "[$a->{menuname}" would cause a compile error)	[reply] [d/l]
Re: How to sort a AoH reference by tlm (Prior) on Jun 01, 2005 at 16:34 UTC
...or, if you want to retain the rest of your code as you showed it, just enclose the RHS of the assignment to `$sorted` in []s: `my $sorted = [ sort { $a->{level} <=> $b->{level} \|\| [$a->{menuname} cmp $b->{menuname} } @$sqldata ];` [download] the lowliest monk	[reply] [d/l]
Re: How to sort a AoH reference by prasadbabu (Prior) on Jun 01, 2005 at 14:39 UTC
my guess is, change $sorted into @sorted. Prasad	[reply]
Re: How to sort a AoH reference by mda2 (Hermit) on Jun 01, 2005 at 17:07 UTC
I think your question are answered... replace, or initialize scalar variable with an array, to change to array context... (all sort function samples use array context) `use Data::Dumper; $Data::Dumper::Indent=0; my @x = sort qw( 1 2 3 4 5 ); my $x = sort qw( 1 2 3 4 5 ); my $y = []; @$y = sort qw( 1 2 3 4 5 ); print Dumper(\@x, $x, $y ); __END__ $VAR1 = [ '1', '2', '3', '4', '5' ]; $VAR2 = undef; $VAR3 = [ '1', '2', '3', '4', '5' ];` [download] But my question... Why don't use mysql todo it as I fetchall_arrayref it from MySQL ?! In my concepts... use perl always... when Perl Power is needs! -- Marco Antonio Rio-PM	[reply] [d/l]
Re: How to sort a AoH reference by TedPride (Priest) on Jun 01, 2005 at 18:19 UTC
use strict; use warnings; my $sqldata = [ { level => 2, menuname => 'cccccc' }, { level => 3, menuname => '333333' }, { level => 3, menuname => '222222' }, { level => 1, menuname => 'CCCCCC' }, { level => 2, menuname => 'bbbbbb' }, { level => 1, menuname => 'BBBBBB' }, { level => 1, menuname => 'AAAAAA' }, { level => 3, menuname => '111111' }, { level => 2, menuname => 'aaaaaa' }, ]; print $_->{level}." ".$_->{menuname}."<br>\n" for sort { $a->{level} <=> $b->{level} \|\| $a->{menuname} cmp $b->{menuname} } @$sqldata; [download]	[reply] [d/l]