Beefy Boxes and Bandwidth Generously Provided by pair Networks
Problems? Is your data what you think it is?

comment on

( #3333=superdoc: print w/replies, xml ) Need Help??

If you're wanting to learn about regular expressions, I'd recommend checking out Mastering Regular Expressions. The author not only explains regular expressions, but also discusses how regular expression engines work and how that impacts the regular expression syntax. It's a good reference book to have handy.

As for your question on (?=\d), that's a zero width look ahead. Basically your second regular expression is looking for the first occurrence of the word 'man' that is immediately followed by a digit and then replaces 'man' with 'cat'. That's assuming that you didn't accidentally forget to include modifiers after the last / in your post.

For example, if your string was man mantis man1 man2 man15, the second regular expression that you provided would change that to man mantis cat1 man2 man15.

In reply to Re: Reading Reg Exp by dasgar
in thread Reading Reg Exp by bharatbsharma

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, 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, 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.
  • Log In?

    What's my password?
    Create A New User
    and the web crawler heard nothing...

    How do I use this? | Other CB clients
    Other Users?
    Others chilling in the Monastery: (9)
    As of 2020-11-29 20:42 GMT
    Find Nodes?
      Voting Booth?

      No recent polls found