Question

Is there a grep function in R that returns TRUE if a pattern is found anywhere in the given character vector and FALSE otherwise?

All the functions I see return a vector of the current positions of each element found.

Answer 1

Are you looking for “any”?

> x<-c(1,2,3,4,5)
> x==5
[1] FALSE FALSE FALSE FALSE  TRUE
> any(x==5)
[1] TRUE

Note that you can do this for strings as well

> x<-c("a","b","c","d")
> any(x=="b")
[1] TRUE
> any(x=="e")
[1] FALSE

And it can be convenient when combined with applies:

> sapply(c(2,4,6,8,10), function(x){ x%%2==0 }  )
[1] TRUE TRUE TRUE TRUE TRUE
> any(sapply(c(2,4,6,8,10), function(x){ x%%2!=0 }  ))
[1] FALSE