grepl in R to find matches to any of a list of character strings

Question

Is it possible to use a grepl argument when referring to a list of values, maybe using the %in% operator? I want to take the data below and if the animal name has \

Answer 1

Try to avoid ifelse as much as possible. This, for example, works nicely

c("Discard", "Keep")[grepl("(dog|cat)", data$animal) + 1]

For a 123 seed you will get

##  [1] "Keep"    "Keep"    "Discard" "Keep"    "Keep"    "Keep"    "Discard" "Keep"   
##  [9] "Discard" "Discard" "Keep"    "Discard" "Keep"    "Discard" "Keep"    "Keep"   
## [17] "Keep"    "Keep"    "Keep"    "Keep"    "Keep"    "Keep"    "Keep"    "Keep"   
## [25] "Keep"    "Keep"    "Discard" "Discard" "Keep"    "Keep"    "Keep"    "Keep"   
## [33] "Keep"    "Keep"    "Keep"    "Discard" "Keep"    "Keep"    "Keep"    "Keep"   
## [41] "Keep"    "Discard" "Discard" "Keep"    "Keep"    "Keep"    "Keep"    "Discard"
## [49] "Keep"    "Keep"