Question

if ‘A*B*C*D*’ is a regular expression, and

string <- c("AB"),

is there a way to check whether the string is accepted by the regular expression? The kind of answer would be yes or no.

Answer 1

Sounds like you’re looking for grep:

> length(grep("^A*B*C*D*$", string)) > 0
[1] TRUE
> length(grep("^A*B*C*D$", string)) > 0
[1] FALSE

I’ve added the ^ and $ to ensure that only the entire string can be matched. If you don’t want that, simply remove them.