2016-10-06 Walking through a String in Swift 3

This is how you walk through a string in Swift 3:

    let str = "Hello, playground"
    let stepsize = 3
    let len = str.characters.count

    for start in stride(from: 0, to: len, by: stepsize) {
        var end = start + stepsize
        if end > len {
            end = len
        }
        
        let startIndex = str.index(str.startIndex, offsetBy: start)
        let endIndex = str.index(str.startIndex, offsetBy: end)

        print("From \(start) to \(end)")
        print(str[startIndex..<endIndex])
    }

Note: not optimized in any way.