I see the pattern that muppetBoy is looking for ... but my solution is not particularly elegant.

The pattern is to pop off two bytes, reverse them, and then append them to a new string. If only one byte is left at the end, prepend an 'F' to it, and append that combination.

My clunky solution that is beggin' to be improved upon: 

my @bytes = split (/([0-9A-F]{2})/, "0102030405060A0BC");
my $new;
foreach (@bytes) {
        next if $_ eq '';
        $new .= (length($_)==2) ? reverse($_) : 'F' . $_;
}

print $new, "\n";

[download]
I thought I knew split well enough, but apparently not as the @bytes array has empty elements in it (hence the hack to check if $_ is empty).

In reply to (jeffa) Re: Rearranging a string by jeffa
in thread Rearranging a string by muppetBoy

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.