Doh! you're absolutely right that my suggestion bails out one element too soon.... However, I don't think your fix changes anything. We need to write the expression so that '0' is TURE but undef and the empty list are FALSE. All of these Deparse the same for me, and all are FALSE-on-0, not TRUE-on-0 as we would like: 
# FALSE-on-0        (bad)
% perl -e 'while($x = 0)       {sleep print "Hello\n"}'
% perl -e 'while(($x = 0))     {sleep print "Hello\n"}'
% perl -e 'while((($x = 0)))   {sleep print "Hello\n"}'
% perl -e 'while(((($x = 0)))) {sleep print "Hello\n"}'

[download]
So, your suggestion of adding those parens around the whole while expression doesn't seem to modify context at all. However, YuckFoo's suggestion will work just fine: 
# TRUE-on-0         (good)
% perl -e 'while(($x) = 0  ) {sleep print "Hello\n"}'

# but FALSE-on-()   (good)
% perl -e 'while(($x) = () ) {sleep print "Hello\n"}'

[download]
Which is exactly what we want.

-Blake

In reply to Re4: Random but non-repeating array loop by blakem
in thread Random but non-repeating array loop by ckohl1

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.