Swift Get string between 2 strings in a string

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: "',")

I'd use a regular expression to extract substrings from complex input like this.

Swift 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

Swift 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

I rewrote one of the top Swift answers to understand what it was doing with map. I prefer a version using guard, IMO.

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