Extracting data from string

Hello

I need to put in $data , the value 18.9 in the string below

842037 root 10 -5 371m 249m 8552 S 18.9 1.2 227:19.97 process

It comes always after a " S " or " R " or " T " or " Z " or " D " , how to do that please ?

Thank you

preg_match('$[SRTZD] ([^ ]+)$', '842037 root 10 -5 371m 249m 8552 S 18.9 1.2 227:19.97 process');

returns


Array
(
    [0] => S 18.9
    [1] => 18.9
)

Thank you!