Swift(1) 基本语法

【适合对象】有一定编程基础的同学

【情景】边看边练，多练多学，自然成长。

【声明】此文章属于原创作品，未经授权，如非法转载，予以追究法律责任。 原文链接：http://www.cnblogs.com/codeAnimal/p/4041545.html

 

练习笔记：

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1.var变量

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1 2	var str = "Hello, playground" println(str)

　2.if语句

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var a = 20 if a > 10 {     println("if 语句，判断条件 无括号"); }

　3.三元运算符

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1 2	var sy = a > 80 ? "真":"假" println(sy)

　4.指定数据类型

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1 2	var a1:Int = 10 println(a1)

　5.注释符号

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　6.数据类型

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1 2	var inta:Int32 = 12 ; println(inta) var floata:Float32 = 10.0 ; println(floata)

　7.控制流 for-in

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let indi = [10,201,30] var teamScore  = 0 for score in indi {     if score > 50{         println(score)     } } 打印结果：201<br><br>//练习2：计算出 字典中，数字最大值  结果：456   let nums = ["prime":[45,456,1,3],"squ":[12,10,32] ] var largest = 0 for(k,n) in nums{     for num in n{         if num > largest{             largest = num         }     } } println(largest)

   //练习1：特殊字符：//..表示 范围

　　var first = 0
　　for i in 0..3{
　　first += i
　　}
　　println(first)

　8.switch语句 （注意：default,必须有）

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let vege = "red peper" var title = "default msg" switch vege{     case "red":         title = "red"     case "red","peper":         title = "2"; case let y where y.hasSuffix("peper")://特殊用法         println(y)         title = "3" default:     title = "ssss"   } println(title)

　9.while

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var n = 2; while n < 50 {     n = n*3 } println(n)

　10.计算字符串的长度 countElements

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var s = "lljkjij " var l = countElements(s) println(l)

　11.字符串相等 == 

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var str1 = "i am liuqinghua" var str2 = "i am liuqinghua" if str1 == str2 {     println("result > "+"==") }else{     println("result >"+"!=") }

　12.数据类型转换

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let num1 = 3 let num2 = 0.1212 var pi = num1 + Int(num2) println(pi)<br><br>打印结果：3

　13. Int? 可选类型

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var strint = "123" let convertedNum:Int? = strint.toInt()  //不确定 strint是纯数字，还是字符串 println("\(convertedNum) result \(convertedNum!)")   // 为可选类型的变量设置nil值，表示没有任何值 var serverResponse:Int? = 404 serverResponse = nil

　14.元组

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//形式1. let httpError = (404,"fail") println(httpError.1)   //形式2. let httpError2 = (status:404,descrip:"fail") println(httpError2.status)

　15.数组

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var shopList:String[] = ["Egg","Milk"]   //追加(append) shopList.append("Flour") println(shopList.count) //数组元素个数   //插入(insert) shopList.insert("Maple",atIndex:shopList.count) println(shopList)   //删除(removeAtIndex) shopList.removeAtIndex(0) println(shopList)   //数组的长度 shopList.count   //遍历1 for item in shopList {     println(item) }   //遍历2 for (index,value) in enumerate(shopList) {     println("Item\(index+1):\(value)") }<br><br>打印结果： index,下标（从0开始）

　16.字典

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var air:Dictionary<String,String> = ["A":"a","B":"b"]   //字典追加 air["C"] = "c" println(air)   //字典删除元素 removeValueForKey let isDel = air.removeValueForKey("A") println(isDel) //"a" (被删除的值 ) println(air)   //字典长度 count属性 air.count   //字典遍历1 for (k,v) in air {     println(k+":" + v) }   //字典遍历2：分别遍历keys和values for key in air.keys {     println(key) } for value in air.values {     println(value) }   //把键转换成数组 let airKey = Array(air.keys) println(airKey)

　17.函数

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func sumOf(nums:Int...) -> Int{     var sum = 0     var j = 0     for n in nums{         sum += n         j++     }     return sum/j       }   //调用方法   var code = sumOf(20,20,20) println(code)

　18.类

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class Test{       //声明变量     var num:Int = 0     var name:String          //构造函数     init(name:String){         self.name = name;     }           //自定义方法，返回String     func simple() -> String{             return name;     }   }   var test = Test(name:"liuqinghua") var name = test.simple()   println(name)   打印结果：liuqinghua