Re^2: sprintf not acting like I expect

[NateTut]

Ok, consider me properly chastised. I don't post too often and I thought it was clear that the numbers were not lining up. Anyway here's the current output:

   2,    3,    5,    7,   11,   13,   17,   19,   23,   29,   31,   37
+,   41,
43,   47,   53,   59,   61,   67,   71,   73,   79,   83,   89,   97, 
+ 101,
103,  107,  109,  113,  127,  131,  137,  139,  149,  151,  157,  163,
+  167,
173,  179,  181,  191,  193,  197,  199,  211,  223,  227,  229,  233,
+  239,
241,  251,  257,  263,  269,  271,  277,  281,  283,  293,  307,  311,
+  313,
317,  331,  337,  347,  349,  353,  359,  367,  373,  379,  383,  389,
+  397,
401,  409,  419,  421,  431,  433,  439,  443,  449,  457,  461,  463,
+  467,
479,  487,  491,  499,  503,  509,  521,  523,  541,  547,  557,  563,
+  569,
571,  577,  587,  593,  599,  601,  607,  613,  617,  619,  631,  641,
+  643,
647,  653,  659,  661,  673,  677,  683,  691,  701,  709,  719,  727,
+  733,
739,  743,  751,  757,  761,  769,  773,  787,  797,  809,  811,  821,
+  823,
827,  829,  839,  853,  857,  859,  863,  877,  881,  883,  887,  907,
+  911,
919,  929,  937,  941,  947,  953,  967,  971,  977,  983,  991,  997,

I would like all the columns to be lined up. Here's some pared down example code:

use strict;
use warnings;

use Data::Dumper::Simple;

sub PrintPrimes
{
   my($Primes, $WrapAt, $Iterations) = @_;

   my $PrimeString = '';
   my $PrimeStrings;
   my $ItLength = length($Iterations);

   foreach my $Prime (@$Primes)
      {
      my $PreviousPrimeString = $PrimeString . "\n";
      $PrimeString .= sprintf("%*.0d", $ItLength, $Prime) . ', ';
      if(length($PrimeString) > $WrapAt)
         {
         push(@$PrimeStrings, $PreviousPrimeString);
         $PrimeString = $Prime . ', ';
         }
      }

   chop($PrimeString);
   $PrimeString .= "\n\n";
   push(@$PrimeStrings, $PrimeString);
   $PrimeString = '';

   foreach my $String (@$PrimeStrings)
      {
      $PrimeString .= $String;
      }

   return($PrimeString);
}


my $Primes;
@$Primes =
(
   2,    3,    5,    7,   11,   13,   17,   19,   23,   29,   31,   37
+,   41,
43,   47,   53,   59,   61,   67,   71,   73,   79,   83,   89,   97, 
+ 101,
103,  107,  109,  113,  127,  131,  137,  139,  149,  151,  157,  163,
+  167,
173,  179,  181,  191,  193,  197,  199,  211,  223,  227,  229,  233,
+  239,
);

print(PrintPrimes($Primes, 80, 1000));

[SuicideJunkie]

From that, I can see that you have 5 characters (incl. space) between each number. The problem is only that you're not putting the proper amount of space before the first number of each row.

The chop and push and loop is odd. I suspect you're doing a lot of string analysis in the middle, instead of pre-calculating the important values. I'd suggest a simple:

my $itemLength = length($iterations);
#account for comma and 1 space extra, but at least 1 number per row!
my $NumPerRow = int(80/($itemLength+2)) || 1; 
my $format = "%0${itemLength}d, ";
while (@primeNumbers)
{
  printf($format, shift @primeNumbers) for (1..$NumPerRow);
  print "\n";
}

There is no need to build up a big string of all the results. IO is buffered by default so many separate prints will be efficient.

[GotToBTru]

Glad I waited until you posted first! But here is my contribution, non-destructive of the array. Replace the while{} with the following:

OUTER: for (my $r = 0; $r < @primeNumbers; $r += $NumPerRow) {
  for (my $c = r; $c - $r < $NumPerRow; $c++) {
    printf $format, $primeNumbers[$c];
    last OUTER if ($c == $#primeNumbers);
  }
  print "\n";
}