Re: Sorting an array of hashes

You should try use diagnostics; when things get tough, and use warnings; unless you really know you wont need it (you seldom can know that), but the hints use warnings and diagnostics would give here isn't trivial to understand.
You are just overdoing your sort criteria:

use strict;
use warnings;

my @AoH = (
       {a => 1,  b  => 2,  c  => 3},
       {a => 1,  b  => 2},
       {a => 1,  b  => 2,  c  => 3,  d  => 4},
       {a => 1}
);

my @AoH_sorted = sort { (keys(%{$b})) <=> (keys(%{$a})) } @AoH;

foreach my $i (0 .. $#AoH_sorted) {
  print "$i\t";
#  if (exists  $AoH_sorted[$i]) { # no need to check if exist when usi
+ng foreach
    my %hash = %{$AoH_sorted[$i]};
    foreach my $key (keys %hash) {
      print "$key\t";
    }
#  }
  print "\n";
}
[download]

gives:

0       c       a       b       d
1       c       a       b
2       a       b
3       a
[download]

Comment on Re: Sorting an array of hashes Select or Download Code

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Re^2: Sorting an array of hashes by amarquis (Curate) on Mar 26, 2008 at 12:39 UTC
It took me a bit to understand the error/solution myself here. $a and $b are set to elements of @AoH, not indexes of @AoH, so there is no need to look up the element as in `%{$AoH[$b]}`, you just directly dereference the hash reference directly as `%{$b}`, correct? I agree on the use warnings; as that 'Use of reference "HASH(########)" as array index at myscript.pl' saves me from my own novice-ness constantly.	[reply] [d/l] [select]
Re^2: Sorting an array of hashes by BKB (Novice) on Mar 27, 2008 at 08:23 UTC
# no need to check if exist when using foreach `#! perl use warnings; use strict; my @x = (1,2,3,4,5); delete $x[2]; for (0..4) { print $x[$_] }` [download]	[reply] [d/l]
Re^3: Sorting an array of hashes by stiller (Friar) on Mar 27, 2008 at 08:57 UTC
Actually, in that case you need to check if the value is defined. The element still exists, and checking for existens doesn't buy you anything.	[reply]
Re^4: Sorting an array of hashes by BKB (Novice) on Mar 27, 2008 at 10:46 UTC
Running the previous version of code: `perl arraydelete.pl Use of uninitialized value within @x in print at arraydelete.pl line 6 +. 1245` [download] Modified as follows using "exists": `#! perl use warnings; use strict; my @x = (1,2,3,4,5); delete $x[2]; for (0..4) { print $x[$_] if exists ($x[$_]) }` [download] Run it to produce: `perl arraydelete.pl 1245` [download]	[reply] [d/l] [select]
Re^5: Sorting an array of hashes by stiller (Friar) on Mar 27, 2008 at 10:57 UTC