in reply to Inertion sort in perl

First, Perl is not C or FORTAN or ASM.
This kind of thing:
for ($i=1; $i lt $n; $i++){....}
is an extremely "rare duck" in Perl!
These i-n (INteger) variables just aren't needed in most cases.

Perl uses a variant of QuickSort and for almost all of your sorting, you should too! This is normally faster than SelectSort. Use the power of the language!

Re-coding your program, 

@a = (8,5,2,4,88,1,5,4,3,2);
@a = sort @a; #same as @a = sort{$a <=> $b}@a;
              #because only digits not alpha/digits
print "@a","\n";
#prints: 1 2 2 3 4 4 5 5 8 88

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Re^2: Inertion sort in perl
by Corion (Patriarch) on Apr 25, 2009 at 15:54 UTC

    Close, but not entirely true:

    >perl -le "print for sort @ARGV" 1 10 2 20
1
10
2
20

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    But with an explicit comparison, it works:

    >perl -le "print for sort{ $a <=> $b } @ARGV" 1 10 2 20
1
2
10
20

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      Yes, we are on the same page here!
      Thanks for emphasizing the difference between ASCII vs numeric sort order!

      Corion is completely correct about this...there is a difference.

      I attach some code that I use for a GUI sort gizmo that doesn't know if it is sorting numbers or alpha-number strings. It uses normal string compare unless both items are strictly numeric and in that case, it uses the "spaceship" operator "<=>" for the compare. 

      sub alpha_num_cmp 
{
  my($a, $b) = @_;
  if (( $a =~ m/\D/) || ($b =~ m/\D/) ) { #look for a non-digit
      return ($a cmp $b);  #if so, then use string compare
      }
 return ($a <=> $b); #otherwise straight numeric comparison
}

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      Ok, a cut-n-paste goof...The above code was one level down in the GUI..Ooops!

      That code compares "columns" of similar things. Here is more code... 

      #!usr/bin/perl -w
use strict;

my @a=(8,5,2,4,88,1,10,20,5,4,3,2);

my @b = sort @a;
print "alpha sort\n";
print "@b\n";

@b = sort {$a<=>$b}@a;
print "numeric sort\n";
print "@b\n";

@b = sort alpha_num_cmp @a;
print "an any sort\n";
print "@b\n";

sub alpha_num_cmp 
{
   if ( ( $a =~ m/\D/) || ($b =~ m/\D/) ) 
   {                       #look for a non-digit
      return ($a cmp $b);  #if so, then use string compare
   }
   return ($a <=> $b); #otherwise straight numeric comparison
}

__END__
prints:
alpha sort
1 10 2 2 20 3 4 4 5 5 8 88
numeric sort
1 2 2 3 4 4 5 5 8 10 20 88
an any sort
1 2 2 3 4 4 5 5 8 10 20 88

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