Swift 4: return Substring index from a String [duplicate]

You can use a regex to match your string, assuming that all substrings end with either a ; or the end of string.

This is the regex you should use:

Substring #(\d+): (.+?)(?:;|$)

It captures the substring number into group 1 and the substring into group 2.

You can use it like this:

extension String {
    func substring(withNSRange range: NSRange) -> String {
        return String(string[Range(range, in: self)!])
    }
}

let string = "Substring #1: Hello World!; Substring #2: My name is Tom"
let regex = try! NSRegularExpression(pattern: "Substring #(\\d+): (.+?)(?:;|$)", options: [])
let matches = regex.matches(in: string, options: [], range: NSRange(location: 0, length: string.utf16.count))
let tuples = matches.map { (Int(string.substring(withNSRange: $0.range(at: 1))), string.substring(withNSRange: $0.range(at: 2))) }
let dict = Dictionary(uniqueKeysWithValues: tuples)

// dict will contain something like [1: Hello World!, 2: My name is Tom]

Edit:

Assuming that the custom end of substring is stored in a variable called customStringEnd, you can create the regex like this:

let regex = try! NSRegularExpression(pattern: "Substring #(\\d+): (.+?)(?:\(NSRegularExpression.escapedPattern(for: customStringEnd))|$)", options: [])