tokens: I want to use the city name as pattern to " grep " the str vector , if match " houston " then put " TX " in the new column , if match Phoenix then put AZ , and so on .
ner_tags: O O O O O O O O O O O B-Code_Block O O B-Variable B-Data_Structure O O O O O O O O O O O O O O B-Data_Structure O O O O O O O O O O O O