preg_replace problem

[zorro]

i just don't get...this prints nothing:

echo preg_replace("/(.*)(\d*)(.*)/","$2","the price is $33 dollars");

I've been using these kind of regexes for several months, usually I
expect it should print 33.
Could some php configuration have changed somehow?

[John Dunlop]

Re: preg_replace problem

zorro wrote:
[color=blue]
> i just don't get...this prints nothing:
>
> echo preg_replace("/(.*)(\d*)(.*)/","$2","the price is $33 dollars");
>
> I've been using these kind of regexes for several months, usually I
> expect it should print 33.[/color]

The Kleene star ('*') is, by default, greedy. In other
words, it matches zero or more of whatever came before while
the rest of the pattern still matches. Your first
subpattern matches the entire subject string, and so the
others match nothing.

http://www.php.net/manual/en/pcre.pattern.syntax.php

--
Jock

[Daniel Andersen]

Re: preg_replace problem

zorro wrote:
[color=blue]
> i just don't get...this prints nothing:
>
> echo preg_replace("/(.*)(\d*)(.*)/","$2","the price is $33 dollars");
>
> I've been using these kind of regexes for several months, usually I
> expect it should print 33.
> Could some php configuration have changed somehow?[/color]

I think the problem is that PHP regexes use \2 to represent the second
matched pattern rather than $2. If you change the second argument to '\2'
you should be fine i think.

Daniel

[gilm]

Re: preg_replace problem


Daniel Andersen wrote:[color=blue]
> zorro wrote:
>[color=green]
> > i just don't get...this prints nothing:
> >
> > echo preg_replace("/(.*)(\d*)(.*)/","$2","the price is $33[/color][/color]
dollars");[color=blue][color=green]
> >
> > I've been using these kind of regexes for several months, usually I
> > expect it should print 33.
> > Could some php configuration have changed somehow?[/color]
>
> I think the problem is that PHP regexes use \2 to represent the[/color]
second[color=blue]
> matched pattern rather than $2. If you change the second argument to[/color]
'\2'[color=blue]
> you should be fine i think.
>
> Daniel[/color]

this will work :

echo preg_replace("/^(\D+)(\d+)(\D+ )$/","\\2","th e price is $33
dollars");