using a regular expression this results in the same thing as your 4 lines do:
my $foo = "0:0A:0C:B:B8:F";
$foo =~ s/([0-9A-F])+:?/length($1) < 2?"0$1":$1/ge;

[download]

update:let's try again

my $foo = "0:0A:0C:B:B8:F";
$foo =~ s/([0-9A-F]+):?/length($1) < 2?"0$1":$1/ge;

[download]
The problem with the initial one was where the + was which would match a series of [0-9A-F], but only the last character would be captured, so the length would always be one and it just happened that it was adding a 0 to the front of that and I missed the B8 thing initially. so ++ to you for the catch.

Which brings the question, which maybe I am not thinking but why would it capture only the last character instead of only the initial character?

-enlil

In reply to Re: Converting MAC Address by Enlil
in thread Converting MAC Address by HiFoo

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.