I haven't used R at all in years and only used it a couple times in passing many years ago to try it out. I searched "R string functions", saw "grep" and wonde

I haven't used R at all in years and only used it a couple times in passing many years ago to try it out. I searched "R string functions", saw "grep" and wondered if there was something I was missing in the author's challenge. Is it because it's using regular expressions they don't consider it the correct answer or is it because they aren't as familiar with regular expressions as some other people are, I wonder?