Swift 3 - 如何提取正则表达式中捕获的组？

我正在使用 Swift 3 并尝试访问捕获的组。

let regexp = "((ALREADY PAID | NOT ALR | PROVIDER MAY | READY | MAY BILL | BILL YOU | PAID)((.|\\n)*))(( \\d+)(\\.+|-+)(\\d\\d))"

// check if some substring is in the recognized text
if let range = stringText.range(of:regexp, options: .regularExpression) {
    let result = tesseract.recognizedText.substring(with:range)
}

我希望能够提取出捕获的最后两个数字（\d\d）所以如果文本是：ALREADY PAID asfasdfadsfasdf 39.15，它会提取15。这是一个正则表达式生成器，显示了我想要的内容。通常情况下，我能够做到$8获取提取的第 8 个组，但我不知道如何在 Swift 3 中做到这一点。

http://regexr.com/3fh1e http://regexr.com/3fh1e

斯威夫特 4、斯威夫特 5

extension String {
    func groups(for regexPattern: String) -> [[String]] {
    do {
        let text = self
        let regex = try NSRegularExpression(pattern: regexPattern)
        let matches = regex.matches(in: text,
                                    range: NSRange(text.startIndex..., in: text))
        return matches.map { match in
            return (0..<match.numberOfRanges).map {
                let rangeBounds = match.range(at: $0)
                guard let range = Range(rangeBounds, in: text) else {
                    return ""
                }
                return String(text[range])
            }
        }
    } catch let error {
        print("invalid regex: \(error.localizedDescription)")
        return []
    }
}
}

example:

let res = "1my 2own 3string".groups(for:"(([0-9]+)[a-z]+) ")

(lldb) 资源 ▿ 2 个元素
▿ 0 : 3 个元素

- 0 : "1my "

- 1 : "1my"

- 2 : "1"   

▿ 1 : 3 元素

- 0 : "2own "

- 1 : "2own"

- 2 : "2"