grep items with special symbols

Question

I am trying use grep to extract item that contains symbols_ and |. When I tried to grep with exact match, it returned all items. How to solve the problem?

string = c("ny_(apple)|store", "mn_(apple)|store", "ok_(apple)|store")
grep("\\ny_(apple)|store\\>", string) #this failed because it returned all three items
[1] 1 2 3

Answer 1

Use (double) backslash escapes:

grep("ny_\\(apple\\)\\|store", string)
#> [1] 1