detect non ascii characters in a string

Question

How can I detect non-ascii characters in a vector f strings in a grep like fashion. For example below I\'d like to return c(1, 3) or c(TRUE, FALSE, TRUE,

Answer 1

Came across this later using pure base regex and so simple:

grepl("[^ -~]", x)
## [1]  TRUE FALSE  TRUE FALSE

More here: http://www.catonmat.net/blog/my-favorite-regex/