[PerlChina] wanna a regex expression

Havel Zhang havel.zhang at gmail.com
Wed Aug 23 04:32:54 PDT 2006


hi yang:

    you can using (?!...) regex extension solve this problem. like follows:
#---------------------
$a = 'how are you today ? "are you ok?" you are welcome!';
$a =~ s/you(?!\sok\?)/hello/ig;
print $a ."\n";
#-------------------
Outputs:
how are hello today ? "are you ok?" hello are welcome!
#-------------------


other regEx extensions:

(?= ... ) if  match ahead successfully, return true.
(?!  ... ) if  match ahead failed, return true.
(?<= ...) if match backwards successfully, return true.
(?<! ... ) if match backwards failed, return true.

Good, luck. :)

Havel Zhang

On 8/23/06, 杨晓亮 < yang.liana at gmail.com> wrote:
>
>        Hi, all!
>      suppose a src string like this: how are you today ? "are you ok?" you
> are welcome!
>      I want this string to be       : how are hello today? "are you ok?"
> hello are welcome!
>
>      I want to use just a regex express to do it. but i cant prevent from
> "are you ok?" being changed to be "are hello ok?".
>      I want to use the *Look ahead* or *Look behind* to solve it. can I ?
>
> Yang.liana
> Aug/23/2006
>
> _______________________________________________
> China-pm mailing list
> China-pm at pm.org
> http://mail.pm.org/mailman/listinfo/china-pm
>



-- 
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