strip out repeated ocurrence of a string

Hello list :) I have this problem, a certain string can contain the following information: $string = ' hi{value1;value2} bye{value1;value3} hi{value1;value4} hi{value1;value2} bye{value1;value2} '; What I want is to be able to get this result: $string = ' hi{value1;value2} bye{value1;value3} hi{value1;value4} bye{value1;value2} '; (the order of appearance doesn't matter) Is it even possible to do this with regular expresions? Or should I first look if there is some kind of match and then apply an str_replace($match,'',$string) and add the $match again? Greetings ! -- Mailed by: UnReAl4U - unreal4u ICQ #: 54472056 www1: http://www.chw.net/ www2: http://unreal4u.com/