r - detect non ascii characters in a string

Question

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

x <- c("fa?ile test of showNonASCII(): details{", 
    "This is a good line", "This has an ümlaut in it.", "OK again. }")

Attempt:

y <- tools::showNonASCII(x)
str(y)
p <- capture.output(tools::showNonASCII(x))

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/