Home » Split string into Array of Arrays [closed]

Split string into Array of Arrays [closed]


If I got correct what you want to receive as a result, then this code would make what you want:

extension Array {
    func chunked(into size: Int) -> [[Element]] {
        return stride(from: 0, to: self.count, by: size).map {
            Array(self[$0 ..< Swift.min($0 + size, self.count)])

let src = "https://stackoverflow.com/questions/55396179/001"apple|red|002|banana|yellow|003|grapes|purple"
let result = src.split(separator: "|").map(String.init).chunked(into: 3)
// result = [["https://stackoverflow.com/questions/55396179/001", "apple", "red"], ["002", "banana", "yellow"], ["003", "grapes", "purple"]]

This will work if you know the expected size of resulting subarrays

You can also remove .map(String.init) from the last line if it’s ok for you that array elements are of type String.SubSequence

  1. Split string by | character
  2. Then append elements that not a number in last subarray of resulted array
  3. If element is number, then add new subarray to resulted array
  4. Repeat 2-3 until you done
let input = "https://stackoverflow.com/questions/55396179/001"apple|red|002|banana|yellow|003|grapes|purple"
let result: [[String]] = input
    .split(separator: "|")
    .reduce(into: []) { result, string in
        guard let _ = Int(string) else {
            result[result.count - 1].append(String(string))
/// result: [["apple", "red"], ["banana", "yellow"], ["grapes", "purple"]]

If you want persist 001 as well, then change result.append([]) to result.append([String(string)]):

[["https://stackoverflow.com/questions/55396179/001", "apple", "red"], ["002", "banana", "yellow"], ["003", "grapes", "purple"]]


This solution expect that your string will start with number or crash otherwise.
If you can’t guaranteed that your string starts with number, that you need to manually check that array not empty in guard block.

With regex you could do something like this with thanks to OOPer’s extension

Add a string extension that splits the string based on a regex pattern.

extension String {
    func split(usingRegex pattern: String) -> [String] {
        //### Crashes when you pass invalid `pattern`
        let regex = try! NSRegularExpression(pattern: pattern)
        let matches = regex.matches(in: self, range: NSRange(0..<utf16.count))
        let ranges = [startIndex..<startIndex] + matches.map{Range($0.range, in: self)!} + [endIndex..<endIndex]
        return (0...matches.count).map { String(self[ranges[$0].lowerBound..<ranges[$0+1].lowerBound]) }

Then split your string based on the pattern [0-9]{3} 3 numbers in a row.

let str = "https://stackoverflow.com/questions/55396179/001"apple|red|002|banana|yellow|003|grapes|purple|004|this|is|a|test|one|005|so|is|this"
let pattern = "[0-9]{3}"
let result = str.split(usingRegex: pattern)

var all:[[String]] = []
for row in result {
    let split = row.split(separator: "|").map({ (substring) in
        return String(substring)
    if split.count != 0 {


I tested this in a playground and got the following result:

▿ 5 elements
  ▿ 3 elements
    - "https://stackoverflow.com/questions/55396179/001"
    - "apple"
    - "red"
  ▿ 3 elements
    - "002"
    - "banana"
    - "yellow"
  ▿ 3 elements
    - "003"
    - "grapes"
    - "purple"
  ▿ 6 elements
    - "004"
    - "this"
    - "is"
    - "a"
    - "test"
    - "one"
  ▿ 4 elements
    - "005"
    - "so"
    - "is"
    - "this"

If you decide you want to exclude the ID from the resulting arrays you can modify the extension return to the following:

return (0...matches.count).map { String(self[ranges[$0].upperBound..<ranges[$0+1].lowerBound]) }

This will switch the return range to use the upperBound instead of lowerBound

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