Splitting A String Of Letters Into 3s In Swift

Swift newbie here. I am trying to convert some of my python code to swift and im stuck at the point where I need to split a string of letters into and array with each item being 3

Solution 1:

An easy and Swifty way to do this is to map an array of chars using the stride and advance functions:

let name =Array("ATAGASSTSSGASTA")

let splitName = map(stride(from: 0, to: name.count, by: 3)) {
    String(name[$0..<advance($0, 3, name.count)])
}

Solution 2:

This is pretty verbose, but it does the job:

let name ="ATAGASSTSSGASTA"let array = reduce(name, [String]()) {
    switch$0.last {
    case .Some(let last) where countElements(last) <3:
        var array =$0
        array[array.endIndex-1].append($1)
        return array
    case .Some(_), .None:
        return$0+ [String($1)]
    }
}

Edit: In Swift 1.2, I think countElements has changed to just count. Not sure, don't have it yet, but the documents make it look that way.

Solution 3:

var nucString = "aatttatatatattgctgatctgatctEOS"let nucArrayChar = Array(nucString)
varnucArray: [String] = []
varcounter: Int = nucArrayChar.countif counter % 3 == 0 {
    forvar startNo = 0; startNo < counter; startNo += 3 {
    println("\(nucArray)\(startNo)")
    nucArray.append(String(nucArrayChar[(startNo)...(startNo + 2)]))
    }
}