Match text surrounded by "{{" and "}}"

Question

I'm looking for a Regex which can do this : My text :

"Blablabla {{ blabla1 }} blablablabla {{ blablabla2 {{ blabla3 }} }} blablabla"

What I want to extract :

"blabla1" and "blablabla2 {{ blabla3 }}"

Does anyone has an idea ?

I tried with : "{{(.)*}}" but it returns "blabla1" and "blabla3"

You want it to return "blabla1" and "blablabla2 {{ blabla3 }}" only? Without "blabla3" ? — joaonlima, Jun 08 '13 at 20:46
For such recursive pattern writing a parser is easier when regex fails — Shiplu Mokaddim, Jun 08 '13 at 21:04

score 10 · Accepted Answer · answered Jun 08 '13 at 20:49

10

You can use balancing groups for counting and matching nested constructs like these. For example:

(?x) {{ ( (?: [^{}]+ | (?<open>{{) | (?<-open>}}) )* (?(open)(?!)) ) }}

answered Jun 08 '13 at 20:49

Qtax

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This is exactly what I wanted, thanks ! (I will read the whole doc about balancing groups also ;) ) – abecker Jun 08 '13 at 20:52
@Qtax: Thank you very much.., i looking for solution for this question " {{}} --> parenthesis ( ) " (?x) \( ( (?: [^()]+ | (?\() | (?<-open>\)) )* (?(open)(?!)) ) \) – Thulasiram Oct 30 '13 at 21:47

score 2 · Answer 2 · answered Jun 08 '13 at 20:50

2

This has nesting, so it’s not a regular grammar. Some regex engines have extensions to handle brace matching, but in general the best way to do this is by simply scanning the string and accumulating output in a List<string> while keeping track of the nesting depth.

answered Jun 08 '13 at 20:50

Jon Purdy

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Which is exactly what balancing groups do for you. And if you want to make it more verbose you can always add comments in the expression. ;-) – Qtax Jun 08 '13 at 20:52

Match text surrounded by "{{" and "}}"

2 Answers2

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