swift(一)
//变量
var intNum:Int = 1 var floatNum:Float = 10.2 //浮点型 var double:Double = 10.3333 //双精度浮点型 var isSuccess:Bool = true //false //布尔类型
var str:String ="hello swift" //字符串
var 名称:String = "tom" //变量名可以用中文、韩文等等
var 🐂:String = "牛" //甚至用unicode也可以
//常量
let str1:String = "hello" //赋值完之后不允许改值
//流程控制
var className:String = "Swift"
switch(className){
case "Chinese":
print("当前课程是语文课")
case "Math":
case "Swift":
}
switch(score){
case 90..<100 //大于等于90小于100
case 10...20 //大于10小于20
}
for(var i = 0;i<100;i++){}
var array:[String] = ["a","b","c" ]
for item in array{
print(item) //自动加上一个换行
}
for (index,value) in array.enumerate(){ //一个循环遍历器
print("第\(index+1)个元素是\(value)")
}
//数组 有序
var array:[Any] //Any可以指任何类型,若是String,则必须是String类型
var array1:[String] = ["a","b"]
var array2:Array<String> = [""]
array1.append("c") //在数组array1后添加一个字符c
array1.insert("A",atIndex:0) //在数组array1的第一个位置添加字符A
//字典 无序
var dict1:Dictionary<String,Any> = Dictionary<String,Any>()//空
dict1["name"]="tom" //键是name,值是tom
dict1["age"] = 18
dict1["gender"] = true
var dict2:Dictionary<String,String> = <"name":"jerry","age":"20"]
dict2["name"] = "小明"
print(dict2)
dict2.removeValueForKey("age")//删掉年龄这个键
let dict3:Dictionary<String,Any> = ["name":"percy"] //let是常量,此时dict3是不可变的