Regex Problem

persistence911 has asked for the wisdom of the Perl Monks concerning the following question:

Please I have a problem with regex splitting of a file I need to split "childhe.com/pas/ apstpldr.dll.html? affid=177194&uid=& guid=4E83C7975FCD4 4B091226646F461D89 1/pas/apstpldr.dll .html?affid=177194 &uid=&guid= 4E83C7975FCD44B091 226646F461D89"

Such that all values between the the first occurence of ? after the last . and the next occurence of / are deleted

So that ? affid=177194&uid=& guid=4E83C7975FCD4 4B091226646F461D89 1 and ?affid=177194 &uid=&guid= 4E83C7975FCD44B091 226646F461D89 are removed.

Thanks

Comment on Regex Problem Select or Download Code

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Re: Regex Problem by kennethk (Abbot) on Jun 30, 2011 at 16:26 UTC
Your post could use a little improvement, such as wrapping input in `<code>` tags and clearly specifying your desired output - I can't really follow your spec. See How do I post a question effectively?. I think you can meet your spec using: `#!/usr/bin/perl -w use strict; $_ = 'childhe.com/pas/ apstpldr.dll.html? affid=177194&uid=& guid=4E83 +C7975FCD4 4B091226646F461D89 1/pas/apstpldr.dll .html?affid=177194 &u +id=&guid= 4E83C7975FCD44B091 226646F461D89'; s/\?.?(?=\/\|$)//g; print;` [download] which outputs: `childhe.com/pas/ apstpldr.dll.html/pas/apstpldr.dll .html` YAPE::Regex::Explain interprets this regular expression as: The regular expression: (?-imsx:\?.?(?=/\|$)) matches as follows: NODE EXPLANATION ---------------------------------------------------------------------- (?-imsx: group, but do not capture (case-sensitive) (with ^ and $ matching normally) (with . not matching \n) (matching whitespace and # normally): ---------------------------------------------------------------------- \? '?' ---------------------------------------------------------------------- .*? any character except \n (0 or more times (matching the least amount possible)) ---------------------------------------------------------------------- (?= look ahead to see if there is: ---------------------------------------------------------------------- / '/' ---------------------------------------------------------------------- \| OR ---------------------------------------------------------------------- $ before an optional \n, and the end of the string ---------------------------------------------------------------------- ) end of look-ahead ---------------------------------------------------------------------- ) end of grouping ---------------------------------------------------------------------- [download] See perlretut for more information on regular expressions.	[reply] [d/l] [select]

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Re: Regex Problem
by kennethk (Abbot) on Jun 30, 2011 at 16:26 UTC

<code>

How do I post a question effectively?

I think you can meet your spec using:

#!/usr/bin/perl -w
use strict;

$_ = 'childhe.com/pas/ apstpldr.dll.html? affid=177194&uid=& guid=4E83
+C7975FCD4 4B091226646F461D89 1/pas/apstpldr.dll .html?affid=177194 &u
+id=&guid= 4E83C7975FCD44B091 226646F461D89';
s/\?.*?(?=\/|$)//g;
print;
[download]

which outputs:

childhe.com/pas/ apstpldr.dll.html/pas/apstpldr.dll .html

YAPE::Regex::Explain interprets this regular expression as:

The regular expression:

(?-imsx:\?.*?(?=/|$))

matches as follows:
  
NODE                     EXPLANATION
----------------------------------------------------------------------
(?-imsx:                 group, but do not capture (case-sensitive)
                         (with ^ and $ matching normally) (with . not
                         matching \n) (matching whitespace and #
                         normally):
----------------------------------------------------------------------
  \?                       '?'
----------------------------------------------------------------------
  .*?                      any character except \n (0 or more times
                           (matching the least amount possible))
----------------------------------------------------------------------
  (?=                      look ahead to see if there is:
----------------------------------------------------------------------
    /                        '/'
----------------------------------------------------------------------
   |                        OR
----------------------------------------------------------------------
    $                        before an optional \n, and the end of
                             the string
----------------------------------------------------------------------
  )                        end of look-ahead
----------------------------------------------------------------------
)                        end of grouping
----------------------------------------------------------------------
[download]

See perlretut for more information on regular expressions.

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