Hi, I'm running R 3.2.1 and im having an unexpected problem... when I run the follwing code it returns an error library(stringr) str_extract("+proj=utm +zone=19 +datum=WGS84 +units=m +no_defs +ellps=WGS84 +towgs84=0,0,0", "+proj=[a-zA-Z0-9]*") But I can't find whats wrong with my code. Thanks Mauricio [[alternative HTML version deleted]]