Highly ASCII-specific, and inefficient, but perhaps mildly interesting. Appears to work, though no absolute guarantees are made of course. Using tr/// is kind of a wart, though, hmm.

sub contains_alpha
{
    use bytes;
    my ($string) = @_;
    my $len = length($string .= "");
    my @b = map{$string & (chr(1<<$_) x $len)} (0..7);
    tr/\x01-\xff/\x01/ for @b;
    my $result =
      (~$b[7]) & ($b[6]) &
      (($b[4] & ~($b[3] & (($b[1] & $b[0]) | $b[2])))
       | ((~$b[4]) & ($b[3] | $b[2] | $b[1] | $b[0])))
      ;
    $result =~ tr/\x00//d;
    length($result);
}

[download]

In reply to Re: Challenge - Creative Way To Detect Alpha Characters by premchai21
in thread Challenge - Creative Way To Detect Alpha Characters by Limbic~Region

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.