Stuck with regexp

Question

I'm stuck with php preg_match_all function. Maybe someone wil help me with regexp. Let's assume we have some code:

[a]a[/a]
[s]a[/s]
[b]1[/b]
[b]2[/b]
...
...
[b]n[/b]
[e]a[/e]
[b]8[/b]
[b]9[/b]
...
...
[b]n[/b]

I need to match all that inside [b] tags located between [s] and [e] tags. Any ideas?

are you saying match a [b] tag's contents between two [s] tags OR two [e] tags or between an [s] tag AND an [e] tag? — smitec, Dec 08 '11 at 23:28
I mean AND. In example given above result should be: 1,2,..,n — Mike Sallivan, Dec 08 '11 at 23:35
Could you give an example of what you want the result to be, given your input? — jwd, Dec 08 '11 at 23:46

score 2 · Answer 1 · answered Dec 08 '11 at 23:45

if your structure is exactly the same as above I would personally avoid regex (not a good idea with these fort of languages) and just check the second char of each line. Once you see an s go into consume mode and for each line until you see an e find the first ] and read in everything between that and the next [

score 1 · Answer 2 · answered Dec 08 '11 at 23:30

1

For simplicity use two preg_match calls.

First to retrieve the list you want to inspect /\[s](.+?)\[e]/s.
And then use that result string and match for the contained /\[b](.+?)\[\/b]/s things.

answered Dec 08 '11 at 23:30

mario

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any way to do it in one step? – Mike Sallivan Dec 08 '11 at 23:37

score 1 · Answer 3 · edited May 23 '17 at 10:34

It looks like you are trying to pattern match something that has a treelike structure, essentially like HTML or XML. Any time you find yourself saying "find X located inside matching Y tags" you are going to have this problem.

Trying to do this sort of work with with regular expressions is a Bad Idea.

Here's some info copy/pasted from a different answer of mine for a similar question:

Some references to similar SO posts which will give you an idea of the difficulty you're getting into:

Regex to match all HTML tags except <p> and </p>
Regex to replace all \n in a String, but no those inside [code] [/code] tag
RegEx match open tags except XHTML self-contained tags - bobince says it much more thoroughly than I do (:

The "Right Thing" to do is to parse your input, maintaining state as you go. This can be as simple as scanning your text and keeping a stack of current tags.

score 0 · Answer 4 · answered Dec 08 '11 at 23:29

0

Regular expressions alone aren't sufficient to parse XML, and this appears to be a simplified XML language here.

answered Dec 08 '11 at 23:29

StilesCrisis

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Stuck with regexp

4 Answers4