正则表达式捕获组迅速

Question

我在字符串中有一个正则表达式搜索方法:

extension String {
    func searchRegex (regex: String) -> Array<String> {
        do {
            let regex = try NSRegularExpression(pattern: regex, options: NSRegularExpressionOptions(rawValue: 0))
            let nsstr = self as NSString
            let all = NSRange(location: 0, length: nsstr.length)
            var matches : Array<String> = Array<String>()
            regex.enumerateMatchesInString(self, options: NSMatchingOptions(rawValue: 0), range: all) {
                (result : NSTextCheckingResult?, _, _) in
                let theResult = nsstr.substringWithRange(result!.range)
                matches.append(theResult)
            }
            return matches
        } catch {
            return Array<String>()
        }
    }
}

它运作良好.但是,如果我有一个正则表达式product_title:\['(.*)'它返回我product_title:[\'Some title bla bla\'但我只需要该部分(.*).

我是swift的新手,但是在python中这个问题通过使用groups()函数解决了.如何在swift中使用捕获组.请举个例子.

Answer 1

NSTextCheckingResult有一个numberOfRanges属性和rangeAtIndex()方法,可以让您获取各个捕获组的范围.因此,如果您想要第一个捕获组而不是整个匹配的字符串,您可以将代码修改为:

        var matches : Array<String> = Array<String>()
        regex.enumerateMatchesInString(self, options: NSMatchingOptions(rawValue: 0), range: all) {(result : NSTextCheckingResult?, _, _) in
            let capturedRange = result!.rangeAtIndex(1)
            if !NSEqualRanges(capturedRange, NSMakeRange(NSNotFound, 0)) {
                let theResult = nsstr.substringWithRange(result!.rangeAtIndex(1))
                matches.append(theResult)
            }
        }