Swift数组/字典/枚举

数组：

//初始化
var someInts = [Int](repeating: 10, count: 3)
var someStrs = [String]()
var someVar = someInts[0]

var someInts = [Int]()
someInts.append(20)
someInts += [40]

//遍历
for item in intsC {
    print(item)
}
for (index, item) in someStrs.enumerated() {
    print("在 index = \(index) 位置上的值为 \(item)")
}

//数组的加和
var intsA = [Int](repeating: 2, count:2)
var intsB = [Int](repeating: 1, count:3)

var intsC = intsA + intsB


//方法
array.isEmpty
array.count

字典：
Swift 字典用来存储无序的相同类型数据的集合，Swift 字典会强制检测元素的类型，如果类型不同则会报错。

var someDict =  [KeyType: ValueType]()
var someDict = [Int: String]()
var someDict:[Int:String] = [1:"One", 2:"Two", 3:"Three"]

我们读取字典是通过

var someDict:[Int:String] = [1:"One", 2:"Two", 3:"Three"]
vae someVar = someDict[1]

遍历字典：

for (key, value) in someDict {
   print("字典 key \(key) -  字典 value \(value)")
}
//或者
for (key, value) in someDict.enumerated() {
    print("字典 key \(key) -  字典 (key, value) 对 \(value)")
}

//遍历键或者值
let dictKeys = [Int](someDict.keys)
let dictValues = [String](someDict.values)
for (key) in dictKeys {
    print("\(key)")
}
for (value) in dictValues {
    print("\(value)")
}

修改字典：

var someDict:[Int:String] = [1:"One", 2:"Two", 3:"Three"]
var oldVal = someDict.updateValue("One 新的值", forKey: 1)

//或者
var oldVal = someDict[1]
someDict[1] = "One 新的值"
var someVar = someDict[1]

//移除键值对
var removedValue = someDict.removeValue(forKey: 2)

和数组一样 字典也有isEmpty, count方法

枚举
简单的说 枚举是一组有共同特性的数据的集合。
枚举类型的定义和使用

enum DaysofaWeek {
    case Sunday
    case Monday
    case TUESDAY
    case WEDNESDAY
    case THURSDAY
    case FRIDAY
    case Saturday
}

var weekDay = DaysofaWeek.THURSDAY
weekDay = .THURSDAY //这个是缩写语法 一旦weekDay被声明为一个DaysofaWeek，你可以使用一个缩写语法（.）将其设置为另一个DaysofaWeek的值：
switch weekDay
{
case .Sunday:
    print("星期天")
case .Monday:
    print("星期一")
case .TUESDAY:
    print("星期二")
case .WEDNESDAY:
    print("星期三")
case .THURSDAY:
    print("星期四")
case .FRIDAY:
    print("星期五")
case .Saturday:
    print("星期六")