检索swift中的substring阵列与正则匹配

Question

有什么方法可以检索字符串中 @ sign前缀的单词数组？

“ @city == xyz和@hobby ==园艺” - ＆gt; [“ @city”，“@hobby”]

我尝试了以下两种方法，但两者都返回一个空数组。

let regexp = "/@\\w*/g"

func matches(for regex: String, in text: String) -> [String] {
    do {
        let regex = try NSRegularExpression(pattern: regex)
        let results = regex.matches(in: text,range: NSRange(text.startIndex..., in: text))
        return results.map {
            String(text[Range($0.range, in: text)!])
        }
    } catch let error {
        print("invalid regex: \(error.localizedDescription)")
        return []
    }
}

extension String {
    func regex (pattern: String) -> [String] {
        do {
            let regex = try NSRegularExpression(pattern: pattern, options: NSRegularExpression.Options(rawValue: 0))
            let nsstr = self as NSString
            let all = NSRange(location: 0, length: nsstr.length)
            var matches : [String] = [String]()
            regex.enumerateMatches(in: self, options: NSRegularExpression.MatchingOptions(rawValue: 0), range: all) {
                (result : NSTextCheckingResult?, _, _) in
                if let r = result {
                    let result = nsstr.substring(with: r.range) as String
                    matches.append(result)
                }
            }
            return matches
        } catch {
            return [String]()
        }
    }
}

Answer 1

@jnpdx在评论中暗示的那样，您的基本问题是您的regexp字符串包含来自另一种语言的控制元素。以下内容应解决您的问题：

let regexp = "@\\w*"

您还会根据Objective-C及其相关类型的转换而陷入不必要的试用语句和过时的API中。以下应该做：

func matches(for regex: String, in text: String) -> [String] {
    var result = [String]()
    var startIndex = text.startIndex
    let endIndex = text.endIndex
    while let range = text.range(of: regex,
                                 options: .regularExpression,
                                 range: startIndex ..< endIndex)
    {
        result.append(String(text[range]))
        startIndex = range.upperBound
    }
    return result
}

Answer 2

在iOS 16+上，您也可以这样写。

let text = "@City == xyz AND @Hobby == gardening"
let regex = /@\w*/

let matches = text.matches(of: regex)
let results = matches.map { String($0.output) }

print(results) // ["@City", "@Hobby"]