Swift 基本语法

//用let声明常量，用var来声明变量，一个常量的值在编译时并不需要获取，但是只能为他赋值一次，

        var myValue = 42;

        myValue = 50;

        var contValue = 42;

//如果初始值没有提供足够的信息(或者没有初始值),那你需要在变量后面声明类型,用冒 号分割

        var value:NSInteger = 45;
        var doubleValue:Double = 60.00;

//删除最后一行中string，

        let apple = 3;

        let orange = 5;

        let appleSummary = "I have \(apple) apples";

        let orangeSummary = "I have \(orange) oranges";

        print(appleSummary);

        print(orangeSummary);

//判断数字串转化为数字是不是不等于空

        if Int(f) != nil {

            print(Int(f));

        }

        

        let str : String = "123456";

        print("字符串长度:",str.characters.count);

 //以什么开始

        print(str.hasPrefix("1"));

        //以什么结尾

        print(str.hasSuffix("6"));

        

     //两个字符串相加

        let str1 : String = "你好，";

        let str2 = str + str1;

        

        print(str2);

 //字符出的截取

        let range : NSRange = NSMakeRange(2, 2);

        let rang1 = (str2 as NSString).substringFromIndex(1);

        let rang2 = (str2 as NSString).substringWithRange(range);

        

        print(rang2);

        

        let st : NSString = "abcdefgh";

        let rang3 : NSRange = NSRange(location: 1,length: 2);

        let strr : NSString = st.substringWithRange(rang3);

        

        print("strr = ",strr);

        

        //获取字符串的长度

        let count = st.length;

        print("count = ",count);

//创建数组

        var arr = [Int]();

        var array : Array = [Int]();

        var arr1 = [1,2,3,4,5];

        let arr2 = Array<Int>();

        print(arr1);

        

        //遍历数组

        for index in arr1 {

            print(index);

        }

        

      //添加数组元素

        array.insert(
4000
1, atIndex: 0);

        print(array);

        

       //删除数组元素

        arr1.removeAtIndex(2);

        print("arr1 = ",arr1);

        //替换元素

        arr1[2] = 78;

        print("arr1 = ",arr1);

//oc数组

        var ocArr : NSMutableArray = NSMutableArray();

        ocArr.addObject("wang");

        ocArr.addObject("ying");

        ocArr.addObject("ying");

        ocArr[0] = "hello";

        print(ocArr);

        print("元素个数：",ocArr.count);

        print("元素个数：\(ocArr.count)");

字典

        var dic : Dictionary = Dictionary<String,String>();

        dic["1"] = "1";

        dic.updateValue("2", forKey: "2");  //有则更改，无则增加

        

        dic.removeAll(keepCapacity: true);

        print(dic);

        

        //oc字典

        let dict : NSMutableDictionary = NSMutableDictionary();

        

        //添加元素

        dict.setObject("dic1", forKey: "dic");

        dict.setObject("dic2", forKey: "dic1");

        //删除元素

//        dict.removeObjectForKey("dic");

        print(dict);

        //修改元素

        dict["dic"] = "hello";

        

        //遍历字典

        for (key,value) in dict {

            print("key = \(key),value = \(value)");

        }

for循环

//循环

        for index in 1...10 {

            print(index);

        }

        for index1 in 1..<10 {

            print(index1);

        }

while 循环

//while 循环

        var whileIndex = 0;

        var sum = 0;

        

        while whileIndex < 5 {

            whileIndex += 1;

            sum += whileIndex;

        }

        print("whileIndex1 = ",sum);

        repeat {

           whileIndex += 1;

            sum += whileIndex;

        }while whileIndex < 10;

        

        print("whileIndex = ",sum);

枚举

 //定义枚举

        enum City : Int {

            

            case beijing=1,guangzhou,shanghai,anyang

            case hangzhou

            case wenzhou

            

        }

        print(City.wenzhou.rawValue);

        

        let  suma = Season.Summer;

        

        switch suma {

        case .Summer:

            print(1);

        case .Spring:

            print(2);

        case .Auto:

            print(2);

        default:

            print("默认");

        }

        
函数

   //无参函数，无返回值

        func func1() {

            

        }

        //有参函数，无返回值

        func func2(aa : Int)

        {

            

        }

        //无参函数，有返回值

        func func3(aa : Int)->Int

        {

            return 2;

        }

        

        //有参函数，有返回值

        func func4(aa : Int)->Int

        {

            return 2;

        }

        

        //有参函数 ，多个返回值

        func func5 (aa : Int)->(Int,Int)

        {

            return(1,2);

        }

        

        //多参数，

        func fun6 (a : Int...)->(Int)

        {

            var result = 0;

            for index in a {

                result = result + index;

            }

            print("result = ",result);

            return 2;

        }