Splitting a string in swift using multiple delimiters

Question

I am trying to split (or explode) a string in Swift (1.2) using multiple delimiters, or seperators as Apple calls them.

My string looks like this:

KEY1=subKey1=value&subkey2=valueKEY2=subkey1=value&subkey2=valueKEY3=subKey1=value&subkey3=value

I have formatted it for easy reading:

KEY1=subKey1=value&subkey2=value
KEY2=subkey1=value&subkey2=value
KEY3=subKey1=value&subkey3=value

The uppercase "KEY" are predefined names.
I was trying to do this using:

var splittedString = string.componentsSeparatedByString("KEY1")

But as you can see, I can only do this with one KEY as the separator, so I am looking for something like this:

var splittedString = string.componentsSeperatedByStrings(["KEY1", "KEY2", "KEY3"])

So the result would be:

[
  "KEY1" => "subKey1=value&subkey2=value",
  "KEY2" => "subkey1=value&subkey2=value",
  "KEY3" => "subkey1=value&subkey2=value"
]

Is there anything built into Swift 1.2 that I can use? Or is there some kind of extension/library that can do this easily?

Thanks for your time, and have a great day!

Answer 1

One can also use the following approach to split a string with multiple delimiters in case keys are single characters:

//swift 4+
let stringData = "K01L02M03"
let res = stringData.components(separatedBy: CharacterSet(charactersIn: "KLM"))

//older swift syntax
let res = stringData.componentsSeparatedByCharactersInSet(NSCharacterSet(charactersInString: "KLM"));

res will contain ["01", "02", "03"]

If anyone knows any kind of special syntax to extend the approach to multiple characters per key you are welcome to suggest and to improve this answer

Answer 2

Swift 4.2 update to @vir us's answer:

let string = "dots.and-hyphens"
let array = string.components(separatedBy: CharacterSet(charactersIn: ".-"))

Answer 3

This isn't very efficient, but it should do the job:

import Foundation

extension String {
  func componentsSeperatedByStrings(ss: [String]) -> [String] {
    let inds = ss.flatMap { s in
      self.rangeOfString(s).map { r in [r.startIndex, r.endIndex] } ?? []
    }
    let ended = [startIndex] + inds + [endIndex]
    let chunks = stride(from: 0, to: ended.count, by: 2)
    let bounds = map(chunks) { i in (ended[i], ended[i+1]) }
    return bounds
      .map { (s, e) in self[s..<e] }
      .filter { sl in !sl.isEmpty }
  }
}



"KEY1=subKey1=value&subkey2=valueKEY2=subkey1=value&subkey2=valueKEY3=subKey1=value&subkey3=value".componentsSeperatedByStrings(["KEY1", "KEY2", "KEY3"])

// ["=subKey1=value&subkey2=value", "=subkey1=value&subkey2=value", "=subKey1=value&subkey3=value"]

Or, if you wanted it in dictionary form:

import Foundation

extension String {
  func componentsSeperatedByStrings(ss: [String]) -> [String:String] {
    let maybeRanges = ss.map { s in self.rangeOfString(s) }
    let inds   = maybeRanges.flatMap { $0.map { r in [r.startIndex, r.endIndex] } ?? [] }
    let ended  = [startIndex] + inds + [endIndex]
    let chunks = stride(from: 0, to: ended.count, by: 2)
    let bounds = map(chunks) { i in (ended[i], ended[i+1]) }
    let values = bounds
      .map { (s, e) in self[s..<e] }
      .filter { sl in !sl.isEmpty }
    let keys = filter(zip(maybeRanges, ss)) { (r, _) in r != nil }
    var result: [String:String] = [:]
    for ((_, k), v) in zip(keys, values) { result[k] = v }
    return result
  }
}


"KEY1=subKey1=value&subkey2=valueKEY2=subkey1=value&subkey2=valueKEY3=subKey1=value&subkey3=value".componentsSeperatedByStrings(["KEY1", "KEY2", "KEY3"])

// ["KEY3": "=subKey1=value&subkey3=value", "KEY2": "=subkey1=value&subkey2=value", "KEY1": "=subKey1=value&subkey2=value"]

For Swift 2:

import Foundation

extension String {
  func componentsSeperatedByStrings(ss: [String]) -> [String] {
    let unshifted = ss
      .flatMap { s in rangeOfString(s) }
      .flatMap { r in [r.startIndex, r.endIndex] }
    let inds  = [startIndex] + unshifted + [endIndex]
    return inds.startIndex
      .stride(to: inds.endIndex, by: 2)
      .map { i in (inds[i], inds[i+1]) }
      .flatMap { (s, e) in s == e ? nil : self[s..<e] }
  }
}

Answer 4

Swift 5:

extension String {
    func components<T>(separatedBy separators: [T]) -> [String] where T : StringProtocol {
        var result = [self]
        for separator in separators {
            result = result
                .map { $0.components(separatedBy: separator)}
                .flatMap { $0 }
        }
        return result
    }
}

It's for the sack of nice and neat code, don't use it if you need something efficiently