Swift获取字符串中2个字符串之间的字符串

Question

我从 html 解析中得到一个字符串；

string = "javascript:getInfo(1,'Info/99/something', 'City Hall',1, 99);"

我的代码类似于

var startIndex = text.rangeOfString("'")
var endIndex = text.rangeOfString("',")
var range2 = startIndex2...endIndex
substr= string.substringWithRange(range)

我不确定我的第二个拆分字符串应该是“'”还是“'”，

我希望我的结果是

substr = "Info/99/something"

Answer 1

extension String {
    
    func slice(from: String, to: String) -> String? {
        return (range(of: from)?.upperBound).flatMap { substringFrom in
            (range(of: to, range: substringFrom..<endIndex)?.lowerBound).map { substringTo in
                String(self[substringFrom..<substringTo])
            }
        }
    }
}

"javascript:getInfo(1,'Info/99/something', 'City Hall',1, 99);"
  .sliceFrom("'", to: "',")

Answer 2

我会使用正则表达式从这样的复杂输入中提取子字符串。

斯威夫特 3.1：

let test = "javascript:getInfo(1,'Info/99/something', 'City Hall',1, 99);"

if let match = test.range(of: "(?<=')[^']+", options: .regularExpression) {
    print(test.substring(with: match))
}

// Prints: Info/99/something

斯威夫特 2.0：

let test = "javascript:getInfo(1,'Info/99/something', 'City Hall',1, 99);"

if let match = test.rangeOfString("(?<=')[^']+", options: .RegularExpressionSearch) {
    print(test.substringWithRange(match))
}

// Prints: Info/99/something

Answer 3

我重写了one of the top Swift answers 以了解它对map 的作用。我更喜欢使用guard，IMO 的版本。

extension String {
    
    func slice(from: String, to: String) -> String? {
        guard let rangeFrom = range(of: from)?.upperBound else { return nil }
        guard let rangeTo = self[rangeFrom...].range(of: to)?.lowerBound else { return nil }
        return String(self[rangeFrom..<rangeTo])
    }
    
}

行为：

let test1 =   "a[b]c".slice(from: "[", to: "]") // "b"
let test2 =     "abc".slice(from: "[", to: "]") // nil
let test3 =   "a]b[c".slice(from: "[", to: "]") // nil
let test4 = "[a[b]c]".slice(from: "[", to: "]") // "a[b"

Answer 4

查找起始字符串和结束字符串之间的所有子字符串：

extension String {
    func sliceMultipleTimes(from: String, to: String) -> [String] {
        components(separatedBy: from).dropFirst().compactMap { sub in
            (sub.range(of: to)?.lowerBound).flatMap { endRange in
                String(sub[sub.startIndex ..< endRange])
            }
        }
    }
}

let str = "start A end ... start B end"
str.sliceMultipleTimes(from: "start", to: "end")    // ["A", "B"]

Answer 5

如果它始终是第二个拆分，则此方法有效：

let subString = split(string, isSeparator: "'")[1]

Answer 6

您可以使用 var arr = str.componentsSeparatedByString(",") 作为您的第二个拆分，它将返回您的数组

Answer 7

斯威夫特 4.2：

extension String {

    //right is the first encountered string after left
    func between(_ left: String, _ right: String) -> String? {
        guard let leftRange = range(of: left), let rightRange = range(of: right, options: .backwards)
            ,leftRange.upperBound <= rightRange.lowerBound else { return nil }

        let sub = self[leftRange.upperBound...]
        let closestToLeftRange = sub.range(of: right)!
        return String(sub[..<closestToLeftRange.lowerBound])
    }

}

Answer 8

考虑使用正则表达式来匹配单引号之间的所有内容。

let string = "javascript:getInfo(1,'Info/99/something', 'City Hall',1, 99);"

let pattern = "'(.+?)'"
let regex = NSRegularExpression(pattern: pattern, options: nil, error: nil)
let results = regex!.matchesInString(string, options: nil, range: NSMakeRange(0, count(string)))  as! [NSTextCheckingResult]

let nsstring = string as NSString
let matches = results.map { result in return nsstring.substringWithRange(result.range)}

// First match
println(matches[0])

Answer 9

斯威夫特 5

extension String {

    ///Returns an empty string when there is no path.
    func substring(from left: String, to right: String) -> String {
        if let match = range(of: "(?<=\(left))[^\(right)]+", options: .regularExpression) {
            return String(self[match])
        }
        return ""
    }
}

Answer 10

在 Swift 4 或更高版本中，您也可以在 StringProtocol 上创建扩展方法来支持子字符串。你可以只返回一个Substring 而不是一个新的字符串：

edit/u[日期：Swift 5

extension StringProtocol  {
    func substring<S: StringProtocol>(from start: S, options: String.CompareOptions = []) -> SubSequence? {
        guard let lower = range(of: start, options: options)?.upperBound
        else { return nil }
        return self[lower...]
    }
    func substring<S: StringProtocol, T: StringProtocol>(from start: S, to end: T, options: String.CompareOptions = []) -> SubSequence? {
        guard let lower = range(of: start, options: options)?.upperBound,
            let upper = self[lower...].range(of: end, options: options)?.lowerBound
        else { return nil }
        return self[lower..<upper]
    }
}

---

let string = "javascript:getInfo(1,'Info/99/something', 'City Hall',1, 99);"
let substr = string.substring(from: "'")                   // "Info/99/something', 'City Hall',1, 99);"
let subString = string.substring(from: "'", to: "',")  // "Info/99/something"

let subStringCaseInsensitive = string.substring(from: "'info/", to: "/something", options: .caseInsensitive)  // "99"

Answer 11

如果你想从字符串的开头或结尾也支持

extension String {
    func slice(from: String, to: String) -> String? {
        return (from.isEmpty ? startIndex..<startIndex : range(of: from)).flatMap { fromRange in
            (to.isEmpty ? endIndex..<endIndex : range(of: to, range: fromRange.upperBound..<endIndex)).map({ toRange in
                String(self[fromRange.upperBound..<toRange.lowerBound])
            })
        }
    }
}

"javascript:getInfo(1,'Info/99/something', 'City Hall',1, 99);"
  .slice(from: "'", to: "',") // "Info/99/something"

"javascript:getInfo(1,'Info/99/something', 'City Hall',1, 99);"
  .slice(from: "", to: ":") // "javascript"

"javascript:getInfo(1,'Info/99/something', 'City Hall',1, 99);"
  .slice(from: ":", to: "") // "getInfo(1,'Info/99/something', 'City Hall',1, 99);"

"javascript:getInfo(1,'Info/99/something', 'City Hall',1, 99);"
  .slice(from: "", to: "") // "javascript:getInfo(1,'Info/99/something', 'City Hall',1, 99);"

---

如果你想要另一种语法，也许更易读

extension String {
    func slice(from: String, to: String) -> String? {
        guard let fromRange = from.isEmpty ? startIndex..<startIndex : range(of: from) else { return nil }
        guard let toRange = to.isEmpty ? endIndex..<endIndex : range(of: to, range: fromRange.upperBound..<endIndex) else { return nil }
        
        return String(self[fromRange.upperBound..<toRange.lowerBound])
    } 
}

Answer 12

Swift 4 版本的@litso。查找文本中的所有值

func find(inText text: String, pattern: String) -> [String]? {
    do {
        let regex = try NSRegularExpression(pattern: pattern, options: .caseInsensitive)
        let result = regex.matches(in: text, options: .init(rawValue: 0), range: NSRange(location: 0, length: text.count))

        let matches = result.map { result in
            return (text as NSString).substring(with: result.range)
        }

        return matches
    } catch {
        print(error)
    }
    return nil
}