LIKE 'beginning%middle%'

y <- c("I am looking for a dog",
       "looking for a new dog", "a dog", "I am just looking")

y<- c("I am looking for a dog", "looking for a new dog", "a dog", "I am just looking")
grep("looking.*dog",y, value=T)
# [1] "I am looking for a dog" "looking for a new dog"

y<- c("I am looking for a dog", "looking for a new dog", "a dog", "I am just looking")
grep("^looking.*dog$", y)
[1] 2