Is there a way to replace regular expressions with low regular expressions?

Is there any other way to format the ab100bc200cd300 string as AB => 100, bc => 200, cd = 300, that is, English + numbers?
Although regular expressions can be used, the efficiency is too low. Is there a way to implement it with others? How can this problem be solved?

Reply to discussion (solution)

$ S = 'ab100bc200cd300 '; preg_match_all ('/([a-z] +) (\ d +)/', $ s, $ m ); $ t = array_combine ($ m [1], $ m [2]); print_r ($ t );

Array ([AB] => 100 [bc] => 200 [cd] => 300)

Is efficiency low? Not seen

Using the moderator method seems to be more efficient. It seems that code optimization is very important.