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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!

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  • Can value, KEYN and subKeyN have & or = in their parameters? Or Can also KEYN be in subKeyN (as a subString?) Commented Sep 8, 2015 at 19:52
  • Do you have control over the way this string is generated ? How do you know when value ends and the key begins ? Could you add another separator ? Commented Sep 8, 2015 at 20:11

8 Answers 8

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29

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

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1 Comment

Some extra things to be aware of here: stackoverflow.com/a/61119561/2079103
17

Swift 4.2 update to @vir us's answer:

let string = "dots.and-hyphens" let array = string.components(separatedBy: CharacterSet(charactersIn: ".-"))
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8

Swift provides a new function split here:

let line = "BLANCHE: I don't want realism. I want magic!" print(line.split(whereSeparator: { $0 == " " || $0 == "."}))
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This looks like a great updated approach. Documentation says it's been available since Swift 8.0+
@clearlight You mean iOS 8.0+ (ain't no Swift 8.0 yet)
5

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] } } }
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2 Comments

Thanks man! worked great, until I updated to the new xcode 7GM and swift 2.0 syntax, do you have any idea how I could change the code so it would work? The "stride()" function is giving me an error: let chunks = stride(from: 0, to: ended.count, by: 2) "Stride(from:to:by) is unavailable" Thanks in advance
Thanks a lot! Works like a charm :)
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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 sake of nice and neat code, don't use it if you need something efficiently

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0

Swift 2 for forward compatibility

Using a regular expression:

let string = "KEY1=subKey1=value&subkey2=valueKEY2=subkey1=value&subkey2=valueKEY3=subKey1=value&subkey3=value" let nsString :NSString = string let stringRange = NSMakeRange(0, string.utf16.count) let pattern = "(KEY\\d)=([^=]+=[^&]+[^=]+?=[^K]+)" var results = [String:String]() do { var regEx = try NSRegularExpression(pattern:pattern, options:[]) regEx.enumerateMatchesInString(string, options: [], range: stringRange) { (result : NSTextCheckingResult?, _, _) in if let result = result { if result.numberOfRanges == 3 { let key = nsString.substringWithRange(result.rangeAtIndex(1)) let value = nsString.substringWithRange(result.rangeAtIndex(2)) results[key] = value } } } } catch { print("Bad Pattern") }

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

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0

You could do it with regular expressions. The below snippet is a bit clumsy and not really fail-safe but it should give you an idea.

let string = "KEY1=subKey1=value&subkey2=valueKEY2=subkey1=value&subkey2=valueKEY3=subKey1=value&subkey3=value" let re = NSRegularExpression(pattern: "(KEY1|KEY2|KEY3)=", options: nil, error: nil)! let matches = re.matchesInString(string, options: nil, range: NSMakeRange(0, count(string))) var dict = [String: String]() for (index, match) in enumerate(matches) { let key = (string as NSString).substringWithRange( NSMakeRange(match.range.location, match.range.length - 1)) let valueStart = match.range.location + match.range.length let valueEnd = index < matches.count - 1 ? matches[index + 1].range.location : count(string) let value = (string as NSString).substringWithRange( NSMakeRange(valueStart, valueEnd - valueStart)) dict[key] = value }

The final value of dict is

[KEY3: subKey1=value&subkey3=value, KEY2: subkey1=value&subkey2=value, KEY1: subKey1=value&subkey2=value]
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3 Comments

Thanks for the answer, I see how it works. But the actual string im using does not have keys that are formatted like "KEYX" where X is the Int. I have keys that are completely different from each other, more like "NS", "AAAA" and "MX". How could I implement an array with these keys in your code? Thank you very much for your time!
@Rick Sorry for the delay. For the record, I updated my answer to support arbitrary key names. The idea is to use an either-or-like expression (KEY1|KEY2|KEY3).
Thanks man, I am currently using oisdk's method of the string extension, which works great, but I will give your method a try and see what works best.
0

This works:

extension StringProtocol { func split(by breaks: [String]) -> [any StringProtocol] { for split in breaks { guard self.contains(split) else { continue } return self.components(separatedBy: split).flatMap({ $0.split(by: breaks) }).filter({!$0.isEmpty}) } return [self] } }

Then you can use it like this

let str = "KEY1=subKey1=value&subkey2=valueKEY2=subkey1=value&subkey2=valueKEY3=subKey1=value&subkey3=value" str.split(by: ["KEY1=", "KEY2=", "KEY3="]) // Output: ["subKey1=value&subkey2=value", "subkey1=value&subkey2=value", "subKey1=value&subkey3=value"]
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