Php intercepts the specified string solution

Php intercepts the specified string $ a = "s =/Toupiao/yulan/pid = 117 & amp; title = 2 & amp; selectform = 1" with such a string, I want to get the pid value, because the pid value is not long, sometimes the pid = 1, pid = 12, pid = 123 .... php intercepts a specified string
$ A = "s =/Toupiao/yulan/pid = 117 & title = 2 & selectform = 1" has such a string. I want to get the pid value in it, because the pid value is not long, sometimes the pid = 1, pid = 12, pid = 123 ......, then how can I extract the pid value? Php truncate string
------ Solution --------------------

$ A = "s =/Toupiao/yulan/pid = 117 & title = 2 & selectform = 1 ";
Preg_match ('/\ bpid = (\ d +)/', $ a, $ r );
Echo $ r [1];

117