<!DOCTYPE html><html><body><?php$input = [ "It is 5 o'clock", "40 days", "No numbers here", "In the year 2000"];$result = preg_filter('/[0-9]+/', '($0)', $input);print_r($result);?></body></html>Array
(
[0] => It is (5) o'clock
[1] => (40) days
[3] => In the year (2000)
)