well, you can write it a little bit shorter...

my $count = 0;
$_ and $count++ for ($x,$y,$z);
if (1 == $count) {
  print "Exactly one variable set\n";
}

[download]
or or even pack the $count and ++ into a do: 
if (1 == do {my $cnt=0; $_ and $cnt++ for ($x,$y,$z); $cnt } {
  print "Exactly one variable set\n";
}

[download]

But I doubt that this is more readable

update: I'd prefer a grep solution as posted by tye

if (1 == grep {$_} ($x,$y,$z)) {
  print "Exactly one variable set\n";
}

[download]

Best regards,
perl -e "s>>*F>e=>y)\*martinF)stronat)=>print,print v8.8.8.32.11.32"

In reply to Re: One out of three ain't bad by strat
in thread One out of three ain't bad by saintmike

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.