[R] Number of occurences of a character in a string

[Santosh Srinivas]

New to R ... which is a function to most effectively search the number of occurrences of a character in a string?

b <- c("jkhrikujhj345hi5hiklfjsdkljfksdio324j';;'lfd;g'lkfit34'5;435l;43'5k")

I want the number of semi-colons ";" in b?

Thanks.