如何使用 swift 对搜索正则表达式进行分组

Question

在正则表达式中，您可以对不同的匹配进行分组以轻松“模式匹配”给定的匹配。

while match != nil {
  match = source.rangeOfString(regex, options: .RegularExpressionSearch)
  if let m = match {
    result.append(source.substringWithRange(m)
      source.replaceRange(m, with: "") 
  }
}

上面的作品 find 找到匹配的范围，但它不能告诉我组。例如，如果我搜索封装在“”中的单词，我想匹配一个“单词”，但快速只获取单词

是否有可能在swift中这样做？

Answer 1

现在 Swift 的正则表达式相当难看——让我们希望尽快获得更多原生支持！你想要的NSRegularExpression 上的方法是matchesInString。使用方法如下：

let string = "This is my \"string\" of \"words\"."
let re = NSRegularExpression(pattern: "\"(.+?)\"", options: nil, error: nil)!
let matches = re.matchesInString(string, options: nil, range: NSRange(location: 0, length: string.utf16Count))

println("number of matches: \(matches.count)")

for match in matches as [NSTextCheckingResult] {
    // range at index 0: full match
    // range at index 1: first capture group
    let substring = (string as NSString).substringWithRange(match.rangeAtIndex(1))
    println(substring)
}

输出：

number of matches: 2
string
words

Answer 2

如果你想收集匹配的字符串，你可以使用它。 （我的答案来自 Nate Cooks 非常有帮助的答案。）

为 Swift 2.1 更新

extension String {
    func regexMatches(pattern: String) -> Array<String> {
        let re: NSRegularExpression
        do {
            re = try NSRegularExpression(pattern: pattern, options: [])
        } catch {
            return []
        }

        let matches = re.matchesInString(self, options: [], range: NSRange(location: 0, length: self.utf16.count))
        var collectMatches: Array<String> = []
        for match in matches {
            // range at index 0: full match
            // range at index 1: first capture group
            let substring = (self as NSString).substringWithRange(match.rangeAtIndex(1))
            collectMatches.append(substring)
        }
        return collectMatches
    }
}

为 Swift 3.0 更新

extension String {
func regexMatches(pattern: String) -> Array<String> {
    let re: NSRegularExpression
    do {
        re = try NSRegularExpression(pattern: pattern, options: [])
    } catch {
        return []
    }

    let matches = re.matches(in: self, options: [], range: NSRange(location: 0, length: self.utf16.count))
    var collectMatches: Array<String> = []
    for match in matches {
        // range at index 0: full match
        // range at index 1: first capture group
        let substring = (self as NSString).substring(with: match.rangeAt(1))
        collectMatches.append(substring)
    }
    return collectMatches
}}

Answer 3

这些家伙怎么样，添加为字符串的扩展？ )) 所有匹配项，所有组 ) self = String 如果您想添加不作为扩展名，则添加 String 参数并将所有 self 替换为您的参数:)

 func matchesForRegexInTextAll(regex: String!) -> [[String]] {

    do {
        let regex = try NSRegularExpression(pattern: regex, options: [])
        let nsString = self as NSString

        var resultsFinal = [[String]]()

        let results = regex.matchesInString(self,
            options: [], range: NSMakeRange(0, nsString.length))

        for result in results {
            var internalString = [String]()
            for var i = 0; i < result.numberOfRanges; ++i{
                internalString.append(nsString.substringWithRange(result.rangeAtIndex(i)))
            }
            resultsFinal.append(internalString)
        }

        return resultsFinal
    } catch let error as NSError {
        print("invalid regex: \(error.localizedDescription)")
        return []
    }
}

Answer 4

提供的所有答案都很好，但我仍将提供用 Swift 2.2 编写的 my String 扩展。

注意的区别：

• 只使用第一个匹配项
• 支持多个捕获组
• 更准确的函数名称（它是捕获组，不匹配）

.

extension String {
    func capturedGroups(withRegex pattern: String) -> [String]? {
        var regex: NSRegularExpression
        do {
            regex = try NSRegularExpression(pattern: pattern, options: [])
        } catch {
            return nil
        }

        let matches = regex.matchesInString(self, options: [], range: NSRange(location:0, length: self.characters.count))

        guard let match = matches.first else { return nil }

        // Note: Index 1 is 1st capture group, 2 is 2nd, ..., while index 0 is full match which we don't use
        let lastRangeIndex = match.numberOfRanges - 1
        guard lastRangeIndex >= 1 else { return nil }

        var results = [String]()

        for i in 1...lastRangeIndex {
            let capturedGroupIndex = match.rangeAtIndex(i)
            let matchedString = (self as NSString).substringWithRange(capturedGroupIndex)
            results.append(matchedString)
        }

        return results
    }
}

使用方法：

// Will match "bcde"
"abcdefg".capturedGroups(withRegex: "a(.*)f")

Answer 5

为 Swift 4 更新

/**
 String extension that extract the captured groups with a regex pattern

 - parameter pattern: regex pattern
 - Returns: captured groups
 */
public func capturedGroups(withRegex pattern: String) -> [String] {
    var results = [String]()

    var regex: NSRegularExpression
    do {
        regex = try NSRegularExpression(pattern: pattern, options: [])
    } catch {
        return results
    }
    let matches = regex.matches(in: self, options: [], range: NSRange(location:0, length: self.count))

    guard let match = matches.first else { return results }

    let lastRangeIndex = match.numberOfRanges - 1
    guard lastRangeIndex >= 1 else { return results }

    for i in 1...lastRangeIndex {
        let capturedGroupIndex = match.range(at: i)
        let matchedString = (self as NSString).substring(with: capturedGroupIndex)
        results.append(matchedString)
    }

    return results
}

使用方法：

// Will match "bcde"
"abcdefg".capturedGroups(withRegex: "a(.*)f")

github 上的要点：https://gist.github.com/unshapedesign/1b95f78d7f74241f706f346aed5384ff