Problem with preg_match expression

[Jørn Dahl-Stamnes]

Hello,

I'm trying to write an expression that will match lines like this:

This is [a] a line[/a] with text
This [w] is also a[/w] a line

but not lines like:

This [a] shall not[/w] match

My expression looks like this:

preg_match("/(.*)\[(.)\](.+)\[\/\2\](.*)/",$line,$matche s)

But it does not match. I have tried to replace \2 part of the string above
with a . and then it match.

If I'm correct, the \2 should referre to the character matched by the .
inside the []... or?

Thanx in advace.

--
Jørn Dahl-Stamnes

http://www.dahl-stamnes.net/dahls/index.php

[John Dunlop]

Re: Problem with preg_match expression

Jørn Dahl-Stamnes wrote:
[color=blue]
> "/(.*)\[(.)\](.+)\[\/\2\](.*)/"[/color]

a) Escape the backreference; e.g.,
/(.*)\[(.)\](.+)\[\/\\2\](.*)/
b) Single-quote the regular expression.

http://www.php.net/manual/en/language.types.string.php#language.types.string.syntax.double

--
Jock

[Jørn Dahl-Stamnes]

Re: Problem with preg_match expression

John Dunlop wrote:
[color=blue]
> Jørn Dahl-Stamnes wrote:
>[color=green]
>> "/(.*)\[(.)\](.+)\[\/\2\](.*)/"[/color]
>
> a) Escape the backreference; e.g.,
> /(.*)\[(.)\](.+)\[\/\\2\](.*)/
> b) Single-quote the regular expression.[/color]

Thanks. I found the answer just before I red your reply here.

--
Jørn Dahl-Stamnes

http://www.dahl-stamnes.net/dahls/index.php