I have a curious piece of code, with an error in it, and while I have found the error, I can't explain the erroneous behavior. Could someone help me understand this?

I have a regex that I'm using to split apart a string, which I have simplified for this example. The regex contains capturing parentheses, and the error is that I also include capturing parentheses when I use the regex later. 

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

   my $r = qr{(.)};

   while ('abc' =~ /($r)/g)
   {
      print "loop $1\n";
   }

   foreach ('abc' =~ /($r)/g)
   {
      print "array $_\n";
   }

[download]

The output is: 

   loop a
   loop b
   loop c
   array a
   array a
   array b
   array b
   array c
   array c

[download]

Removing either set of capturing parentheses fixes the problem, but I don't see how the while loop doesn't also get duplicate results?

In reply to Double Capturing Parentheses by pbeckingham

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