How to str_detect a string that contains parentheses?

April 5, 2023

I am trying to do a string search for multiple strings on one column, but the script does not return strings that have parentheses.

a <-  c("Apple", "Facebook", "Google (1992)")
b <- c(1, 2, 3)

c <-  data.frame(a, b)

d <- c %>% 
  distinct(a) %>% 
  pull()

c %>% 
  filter(str_detect(a, paste(d, collapse = "|"))) %>% 
  group_by(a) %>% 
  tally()

I want the last script to return "Apple", "Facebook", "Google (1992)", but it only returns the first two. Is there something I can add to the "collapse" argument to include strings with parentheses?

>Solution :

(Per the comments, you don’t even need regex in this case. But for future reference:) As you may already know, parentheses have to be escaped in regular expressions. This is easy enough when you’re specifying the pattern directly — e.g., str_detect(a, "Google \\(1992\\)"). But it can be slightly trickier when the pattern is stored in a variable, as in your case. You can handle this as

library(stringr)

str_detect(a, paste(
  str_replace_all(d, c("\\(" = "\\\\(", "\\)" = "\\\\)")), 
  collapse = "|"
))

In the vector of replacements, we have to escape the parenthesis on the left side ("\\("). But on the right hand side, we have to escape the "\" — we use "\\\\" to insert a literal "\\".