I have an array of strings (some of which may possibly contain characters in the range \x7f-\xff. I need to concatenate all the strings together at some point. Originally I had:

    $combine = join('',@ret);

[download]

However a for some reason (lost in the mists of time, I suspect it was something to do with efficiency for a few important cases) I changed all the concatenations to:

    $combine = pack("a*" x ($#ret + 1), @ret);

[download]

Now that worked for a considerable time until I recently discovered an unexpected behaviour. This can be illustrated by:

foreach my $item (@ret)
  {
    if($item =~ /([\x7f-\xff])/)
      {
        print "Array     ...".substr($`,-5)." ||".$1.
                  "|| ".substr($',0,5)."\n";
      }
   }

my $via_join = join('',@ret);
if($via_join =~ /([\x7f-\xff])/)
  {
    print "Join     ...".substr($`,-5)." ||".$1.
                  "|| ".substr($',0,5)."\n";
  }

my $via_pack = pack("a*" x ($#ret+1),@ret);
if($via_pack =~ /([\x7f-\xff])/)
  {
    print "Pack     ...".substr($`,-5)." ||".$1.
                   "|| ".substr($',0,5)."\n";
  }

[download]

Which prints out:

Array ...s Neg ||≤|| cios
Join ...s Neg ||≤|| cios
Pack ...s Neg ||├|| │cios

Why does the pack modify the character? Is there a better way to concatenate or will I have to discover why I rejected join() all those months ago?

This is running under 5.8.6 on a Windows XP machine. The text strings orginated in an XML file (ie using ó) and are meant to be "utf-8".

Thanks for any help

In reply to Various ways to concatenating an array of strings by hawtin

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