gistfile1.txt

func lengthEncoding(str: String){

    let chrArr = Array(str)
    var count = 0
    var previous : Character = chrArr[0]
    var finalString = ""

    for (_, item) in chrArr.enumerated() {
        if previous == item{
            count += 1
        }else{

            finalString = finalString + previous.description + count.description
            count = 1
        }
        previous = item
    }

    print(finalString + previous.description + count.description)

}