Beefy Boxes and Bandwidth Generously Provided by pair Networks
good chemistry is complicated,
and a little bit messy -LW
 
PerlMonks  

comment on

( [id://3333]=superdoc: print w/replies, xml ) Need Help??
Why your regex matches the string can be explained like this:
"(?=hello)" matches "hello" ".*" matches "hello Ga" "[^G]" matches "g" "[^a]" matches "s" ".*" matches nothing
Your regex properly skips matching [^G][^a] with "Ga" but will happily match stuff after that. You probably want to do something like this with a negative look ahead:
( "hello Gags" =~ /^(?=hello)(?!.*Ga/ )&& print ("Matched") || print ( +"Unmatched")
Update
To answer your question about how debugging, I find that throwing in a few capturing parens, can often help you to see what is being matched. Here is is a simple example:
use strict; ( "hello Gags" =~ /^(?=hello)(.*)([^G][^a])(.*)$/ ) ? matches() : pri +nt ("Unmatched"); sub matches { no strict 'refs'; for (1..10) { my $tmp = ${$_} or next; print "\$$_ = '$tmp'\n"; } return 1; } __OUTPUT__ $1 = 'hello Ga' $2 = 'gs'

In reply to Re: Debugging Regexes by fletcher_the_dog
in thread Debugging Regexes by perlgags78

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 surveying the Monastery: (4)
As of 2024-03-29 09:07 GMT
Sections?
Information?
Find Nodes?
Leftovers?
    Voting Booth?

    No recent polls found