Split string to arrays with maximum variables in each array - swift

Question

I have a string of numbers (each number is separated by ,) that looks like this:
"12,3,5,75,584,364,57,88,94,4,79,333,7465,867,56,6,748,546,573,466"
I want to split the string to an array of strings, that each element is a string that has maximum 10 number in it.
For the example I've added I want to achieve something like this:
stringsArray:
Element 0: "12,3,5,75,584,364,57,88,94,4"
Element 1: "79,333,7465,867,56,6,748,546,573,466"
And so on...
I've been thinking a lot about a way to do this with Swift, but couldn't find anything...
Does anybody has an idea?
Thank you!

Answer 1

Step 1 - get fully separated array:
let numbers = "12,3,5".components(separatedBy: ",")
Step 2 - chunk your result to parts with ext:
extension Array {
func chunked(by chunkSize: Int) -> [[Element]] {
return stride(from: 0, to: self.count, by: chunkSize).map {
Array(self[$0..<Swift.min($0 + chunkSize, self.count)])
}
}
}
let chunkedNumbers = numbers.chunked(by: 10)
Step 3:
let stringsArray = chunkedNumbers.map { $0.joined(separator: ",") }
Result: ["12,3,5,75,584,364,57,88,94,4", "79,333,7465,867,56,6,748,546,573,466"]
Link to gist playground.

Answer 2

I would look at the position of 10th comma in your original string, get the prefix up to this position, remove this prefix and repeat until remaining string is empty.
This is a bit brute force, but works.
I first add extension to String for convenience.
extension String {
func startIndexesOf(_ string: String) -> [Int] {
var result: [Int] = []
var start = startIndex
while let range = range(of: string, options: .literal, range: start..<endIndex) {
result.append(range.lowerBound.encodedOffset)
start = range.upperBound
}
return result
}
subscript (r: Range<Int>) -> String {
let start = index(self.startIndex, offsetBy: r.lowerBound)
let end = self.index(self.startIndex, offsetBy: r.upperBound)
return String(self[Range(start ..< end)])
}
}
let test = "12,3,5,75,584,364,57,88,94,4,79,333,7465,867,56,6,748,546,573,466,999"
var remaining = test
var arrayOf10 : [String] = []
repeat {
let indexes = remaining.startIndexesOf(",")
if indexes.count < 10 {
arrayOf10.append(remaining) // Just add what remains
break
}
let position = indexes[9]
let endBeginning = remaining.index(test.startIndex, offsetBy: position) // Beginning of what remain to parse
let beginningSubstring = remaining[remaining.startIndex ..< endBeginning]
let beginningText = String(beginningSubstring)
arrayOf10.append(beginningText)
let startNext = remaining.index(test.startIndex, offsetBy: position+1) // What will remain to parse after taking out the beginning
let remainingSubString = remaining[startNext ..< remaining.endIndex]
remaining = String(remainingSubString)
} while remaining.count > 0
for (c, s) in arrayOf10.enumerated() { print("Element", c, ": ", s)}
This will print as desired
Element 0 : 12,3,5,75,584,364,57,88,94,4
Element 1 : 79,333,7465,867,56,6,748,546,573,466
Element 2 : 999