Beefy Boxes and Bandwidth Generously Provided by pair Networks
go ahead... be a heretic
 
PerlMonks  

comment on

( [id://3333]=superdoc: print w/replies, xml ) Need Help??
Possibly, I don't know what your exact ideas are :-) At least .+? is not an optional match for one or more things.

But I've also noticed that a lot of people use non-greedy matching as if it's some sort of magical negative lookahead. It isn't. It will do whatever it takes to match, even if that means also eating one or more of the character(s) that directly follows the non-greedy match (and exiting the repeat at some later instance of that character(s) instead). If your regex has only one match of a non-fixed length you can usually get away with this, but especially if there are more than one them, the semantics can get unexpected.

If you don't want to match something, it's almost always better to just say that. So in your case that would be:

s/<body[^>]+>/.../
(also notice that greedy or non-greedy becomes irrelevant if you write it like this) It would of course still not work as expected (the + should be a * since matching 0 times should be allowed too), but at least the problem now will be not doing anything at all instead of changing too much. And it will keep working as expected even if you make your regex more complicated.

In reply to Re^3: Non-greedy regex behaves greedily by thospel
in thread Non-greedy regex behaves greedily by fourmi

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post; it's "PerlMonks-approved HTML":



  • Are you posting in the right place? Check out Where do I post X? to know for sure.
  • Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:
    <code> <a> <b> <big> <blockquote> <br /> <dd> <dl> <dt> <em> <font> <h1> <h2> <h3> <h4> <h5> <h6> <hr /> <i> <li> <nbsp> <ol> <p> <small> <strike> <strong> <sub> <sup> <table> <td> <th> <tr> <tt> <u> <ul>
  • Snippets of code should be wrapped in <code> tags not <pre> tags. In fact, <pre> tags should generally be avoided. If they must be used, extreme care should be taken to ensure that their contents do not have long lines (<70 chars), in order to prevent horizontal scrolling (and possible janitor intervention).
  • Want more info? How to link or How to display code and escape characters are good places to start.
Log In?
Username:
Password:

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

How do I use this?Last hourOther CB clients
Other Users?
Others browsing the Monastery: (5)
As of 2024-04-23 20:25 GMT
Sections?
Information?
Find Nodes?
Leftovers?
    Voting Booth?

    No recent polls found