//宣告 （可以放入 屬性、布林值、字串）
Ver = 變數（可以改變）
Let = 常數（不能改變）
//型別：
Int = 整數
Float = 浮點數
Double = 雙精度浮點數
// 字串 （字串需要用"將字包起來" ）
String = 字串
//布林值 Bool
True = 對
False = 不對//值的型別不同 不能互相運算，需要將值轉換成同型別
例：
var age:Int = 18
var year:Float = 3.5
age * year = X // 錯誤
// 需要將兩個值轉換成同型別
Float(age) * year = 63 //正確
例2:
let agt:int = 5
agt / 2 = 2 //錯誤 應該是2.5
// 由於age宣告時是int 所以答案只能是int
// 如果答案會是浮點數，請轉換型別
Double(age) / 2 = 2.5 //此時才會出現正確答案// 字串結合用法
例：
var friestName:String = "winnie"
var secondName:String = "will"
var allName:String = "\\(friestName) live \\(secondName)"
print (allName)
var happy:String = "happy"
var ValentinesDay:String = "Valentines Day"
print ("\\(happy) \\(ValentinesDay)")
var friesAge:Int = 29
var secondAge:Int = 30
print ("\\(friestName) is \\(friesAge) yearold \\n \\(secondName) is \\(secondAge) yearold \\n \\(friestName) is so miss \\(secondName) and \\n \\(secondName) is too")
// 字串結合用法2 方便debug版
var friestName:String = "winnie"
var secondName:String = "will"
var allName:String = "\\(friestName) live \\(secondName)"
//print (allName)
var happy:String = "happy"
var ValentinesDay:String = "Valentines Day"
var love = happy + ValentinesDay
var friesAge:Int = 19
var secondAge:Int = 20
var str = ("This is a romantic story \\n \\(allName)\\n\\(friestName) is \\(friesAge) yearold \\n \\(secondName) is \\(secondAge) yearold \\n \\(friestName) is so miss \\(secondName) and \\n \\(secondName) is too \\n In the today I need say I Love You \\(friestName) \\(love)")
print (str)
// 陣列 Array
// 陣列要存的都要同一個型別
var 名稱 = ["0","1","2","3"] // 數字為陣列內的元素位置
名稱[元素號碼] = 顯示該元素內容
名稱＋.count = 統記這名稱內的列陣數量
名稱＋.append("內容") = 新增一個元素到列陣『最後面』
名稱＋.insert("內容",at:數字) = 新增一個元素進去陣列『指定位置』
名稱＋.remove(at:數字) = 移除『指定位置』的內容
名稱＋.removeLast() = 移除『最後一個』內容
名稱＋.removeFrist() = 移除『第一個』內容
名稱＋.reverse() = 反轉順序
名稱[想更改的元素位置] = "要換進去的內容" //要取代原本位置內容的方式
var 名稱 = [型別]() / var 名稱:[型別] = [] // 兩者一樣都可以呈現空白陣列// 元組 Tuple
var colors = ("red","orange","yellow","green")
colors.2 //會拿出orange