in reply to split hash into two columns

An alternative: 
my @keys = sort { $hash{$b} <=> $hash{$a} || $b cmp $a } keys %hash;

my @col1 = splice(@keys, 0, $#keys/2+1);
my @col2 = @keys;

while (@col2) {
   my $key1 = shift(@col1);
   my $key2 = shift(@col2);
   printf "%s => %s\t%s => %s\n",
      $key1, $hash{$key1},
      $key2, $hash{$key2};
}

while (@col1) {
   my $key1 = shift(@col1);
   printf "%s => %s\n",
      $key1, $hash{$key1};
}

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Updated and tested.

Incorrect original version: 

my @col1;
my @col2;

my $t = 0;

foreach (sort {$hash{$b} <=> $hash{$a} || $b cmp $a} keys %hash) {
   if ($t ^= 1) {
      push(@col1, $_);
   } else {
      push(@col2, $_);
   }
}

printf "%s\t%s\n", pop(@col1), pop(@col2)
   while @col2;

printf "%s\n", pop(@col1)
   while @col1;

[download]

Replies are listed 'Best First'.
Re^2: split hash into two columns
by Anonymous Monk on Mar 27, 2006 at 23:15 UTC
    Hi.

    2 questions for you. I modified this code so I could save all the data.

    What is $t ^= 1 doing? I've never seen ^= before.

    Secondly, this is resulting in the data being separated from left to right order, not verticle.

    10  9
8   7
6   5
4   3

    [download]
    instead of 
    10  5
9   4
8   3
7   2
6   1

    [download]
    How can I change it? Thanks!
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      Oops! Fixed in original node. I also made the code print both the keys and the values.

      $a ^= $b is a shortcut for $a = $a ^ $b. Both operators are documented in perlop. In context, $t ^= 1 causes $t and the return value of the expression to flip-flip between zero and one every time it is executed (assuming $t is originally zero or one).

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