Re: Extraction of List of Coordinates

You're using a hash, but you're treating it as an array. Here's your code with the fix, and using an array.

foreach $element (@list_of_Num_Extraction)
   {
      if ($element =~ m/^([0-9]+),([0-9]+)$/)
      {
         my $first_num   = $1;
         my $second_num  = $2;
         my $current_num = ($first_num-1)*$NumOfColumns + $second_num;

         $Unique_Num_List[$current_num] = "($first_num,$second_num)";
      } 
      elsif ($element =~ m/^([0-9]+),([0-9]+):([0-9]+),([0-9]+)$/)
      {
         my ($num1x,$num1y,$num2x,$num2y) = ($1,$2,$3,$4);

         # Swap
         if ($num1x > $num2x)
         { $num1x ^= $num2x; $num2x ^= $num1x; $num1x ^= $num2x; }
         if ($num1y > $num2y)
         { $num1y ^= $num2y; $num2y ^= $num1y; $num1y ^= $num2y; }

         my $counter1 = 0;
         my $counter2 = 0;

         foreach $counter1 ($num1x .. $num2x) {
         foreach $counter2 ($num1y .. $num2y) {
            
            my $current_num = ($counter1-1)*$NumOfColumns + $counter2;
            $Unique_Num_List[$current_num] = "($counter1,$counter2)";
         }}
      }
   }
}
[download]

Comment on Re: Extraction of List of Coordinates Download Code

Replies are listed 'Best First'.
Re^2: Extraction of List of Coordinates by Roy Johnson (Monsignor) on Oct 06, 2004 at 02:39 UTC
In Perl, swaps can be accomplished thus: `if ($num1x > $num2x) { ($num1x, $num2x) = ($num2x, $num1x) }` [download] Caution: Contents may have been coded under pressure.	[reply] [d/l]
Re^3: Extraction of List of Coordinates by sgifford (Prior) on Oct 06, 2004 at 05:28 UTC
I was going to point out the same thing, and that doing it the Perl way is actually faster, but it turns out ikegami's XOR trick is slightly faster: Read more... (1026 Bytes)	[reply] [d/l] [select]
Re^4: Extraction of List of Coordinates by Roy Johnson (Monsignor) on Oct 06, 2004 at 15:31 UTC
After compensating for everything I could think of, XOR still won. Surprisingly, it won against the standard temp-variable swap. Incredibly, it won against a sub that simply returned the numbers in reverse order (in fact, temp swapping generally beat that, too!). I could only think that it wins because the integer math makes things simpler internally. I tried different types of arguments, and preprocessing the argument list to force it to integer. Speedup was slight, if there was any at all, for the integer-forced versions. Perl swapping lost pretty consistently in all cases. Temp swapping and return-value swapping beat XOR for swapping strings, sometimes. I got inconsistent results. Benchmark code follows... Read more... (2 kB) Caution: Contents may have been coded under pressure.	[reply] [d/l]