How to split a string at the last occurence of a sequence

Target: A string with a built-in separator shall be split in an int and another string. In the case that the separator sequence '###' occurs more than once, the string shall always be spliced at the last '###'.

Is there an operator like string.lastIndexOf("###"), like in C#?

This is how my parser looks like:

func parseTuple(from string: String) -> (String, Int)? {
    let parsedString = string.components(separatedBy: "###")
    if let tupleString = String(parsedString[0]), let tupleInt = Int(parsedString[1]) {
        return (tupleString, tupleInt)
    } else {
        return nil
    }
}