BTW, the use of the statement  map { /.+/g } to filter out undefined values works only if the warning about uninitialized values in pattern matches is turned off, and has the additional shortcoming of filtering out empty strings.

Much better, IMO, to grep for only defined values (single-quotes used in example instead of double-quotes to avoid lots of escaping on XP command line): 

>perl -wMstrict -MData::Dumper -le
"my $str = q{1,2,3,4,'fine', '', 'day','today',};
 my @f =
   grep defined,
   $str =~ m{ (\d+) | ' ([^']*) ' }xmsg
   ;
 print Dumper \@f;
"
$VAR1 = [
          '1',
          '2',
          '3',
          '4',
          'fine',
          '',
          'day',
          'today'
        ];

[download]

In reply to Re: Understanding regular expressions: why do I have to use map to clear up undefs in regex output? by AnomalousMonk
in thread Understanding regular expressions: why do I have to use map to clear up undefs in regex output? by corenth

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.