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Re: regex: something...(!something)...something

by Roy Johnson (Monsignor)
on Jul 17, 2008 at 19:41 UTC ( #698429=note: print w/replies, xml ) Need Help??

in reply to regex: something...(!something)...something

My tutorial on look-ahead and look-behind covers this. You're specifying that the open tag is not followed immediately by another open tag; you want to specify that it's followed by any arbitrary text that isn't an open tag. This s/// expression should do what you want:
$x =~ s{(?<=<td>)((?:(?!<td>).)*)3((?:(?!</td>).)*)(?=</td>)}{$1a$2};
Update: I should have broken this down in commented style (I also note that I could have done lookahead for everything after the 3):
$x =~ s{(?<=<td>) # Start match with open-tag ( # Capture (?:(?!<td>).)* # Any number of characters that do not star +t an open-tag )3 # Close capture; match literal 3 (?= # Look ahead to match (?:(?!</td>).)* # Any number of characters that do not star +t a close-tag </td> # then a close-tag )} # End lookahead and pattern {$1a}x;

Caution: Contents may have been coded under pressure.

Replies are listed 'Best First'.
Re^2: regex: something...(!something)...something
by aaaone (Initiate) on Jul 18, 2008 at 12:44 UTC
    Thank you! It also works (I see it is more complex then Oluses regex, but probably more universal). I'll read your tutorial and will try to never ask again stupid questions about regexes :)

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[shmem]: perl -e 'warn "test$/", ^@^ '
[Eily]: well, at least it's right about warn doing the same thing as die :)
[shmem]: same with undef as last element
[msh210]: oh, good point. It's the best kind of correct
[shmem]: msh210: but I'd not call it a lie outright. That's when you do know the truth.
[msh210]: I don't have sendmail (I'm on MS Windows), so does one of you think you can report the bug?
[shmem]: msh210: 'tis about time to tell the sad truth to perl5porters - via perlbug
[msh210]: probably whoever wrote that actually knows the truth
[shmem]: msh210: you can save the perlbug text in a file and send that via your mail agent of choice
[msh210]: hm, okay, I'll try, thanks

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