r - find multiple strings using str_extract_all

Question

I have a list of strings as follows:

tofind<-c("aaa","bbb","ccc","ddd")

I also have a vector as follows:

n<-c("aaabbb","aaa","aaacccddd","eee")

I want to find all matches of my tofind string so that the output should be:

aaa,bbb
aaa
aaa,ccc,ddd

I think I can use str_extract_all but it doesn't give my the expected output

library(stringr)
sapply(n, function(x) str_extract_all(n,tofind)

How do I get the expected output?

Answer 1

You could create a single regex:

tofind <- paste(c("aaa","bbb","ccc","ddd"), collapse="|")

str_extract_all(n, tofind)

[[1]]
[1] "aaa" "bbb"

[[2]]
[1] "aaa"

[[3]]
[1] "aaa" "ccc" "ddd"

[[4]]
character(0)