Extracting numbers from vectors of strings

Question

I have string like this:

years<-c(\"20 years old\", \"1 years old\")

I would like to grep only the numeric number from this vector. Expe

Answer 1

I think that substitution is an indirect way of getting to the solution. If you want to retrieve all the numbers, I recommend gregexpr:

matches <- regmatches(years, gregexpr("[[:digit:]]+", years))
as.numeric(unlist(matches))

If you have multiple matches in a string, this will get all of them. If you're only interested in the first match, use regexpr instead of gregexpr and you can skip the unlist.