Hi

could someone please be so kind to explain me the difference between line 137 and line 140?

  DB<136> @list= ("a".."c","DBIC","A".."C","DANCER","a".."c")
 => ("a", "b", "c", "DBIC", "A", "B", "C", "DANCER", "a", "b", "c")
 
  DB<137> for (@list) { push @result,$_ if /DBIC/.. /DANCER/ and ! // 
+ } 
 => ""
 
  DB<138> @result 
 => ("A", "B", "C")
 
  DB<139> grep { /DBIC/.. /DANCER/ and //  } @list 
 => ("DBIC", "A", "B", "C", "DANCER")
 
  DB<140> grep { /DBIC/.. /DANCER/ and ! //  } @list 
 => ()

[download]

For an explanation of the empty regex // please see Re: grep trouble and Re^4: grep trouble (body of flip-flop range).

Cheers Rolf

In reply to Bug with "last successfully matched regular expression" (empty regex) by LanX

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.