Swift Learning notes a basic data type and simple statement syntax

First Program

New Xcode project, language selection Swift

Once the project is established, it can be run directly command+r.
Modify the program Viewcontroller.swift

////Viewcontroller.swift//H?ello Swift////Created by Xie Han Festival on 15/6/9.//Copyright (c) 2015 WHR. All rights reserved.//ImportUIKitclassViewcontroller:uiviewcontroller {OverrideFunc Viewdidload () {Super. Viewdidload () print ("Hello Swift")additional setup after loading the view, typically from a nib.}OverrideFunc didreceivememorywarning () {Super. Didreceivememorywarning ()//Dispose of any resources, can be recreated.}}

After running, output Hello Swift.

You can see that the overall framework is very similar to OBJECTC and the syntax is different. It is strange that every line is useless;

Variable and logical syntax variable definition

varA= the                    //Variant type, VAR is used to define variablesA= - Letconstantvariable= -    //define a constantLeft double:double =Ten     //Specify constant typeString(constantvariable)//Type conversion, which is much more convenient than OC LetMerge="The first one is \ (a)"      the//string contains a valuevarlist=["a","B","C","D"]//Array definitionlist[1] ="B1"                     //array can be directly assigned to a value Letemptyarray=String[]()//define an empty array Letemptydictionary=dictionary<String,list> ()//define an empty dictionaryvarCannil:String? ="ABC"  //Optional

Cycle

foriteminlist{}遍历词典和数组for (itemin array{    forinitem{    }}

Conditions

ifa>10 {   //苹果为什么不搞和c java 类似的语法呢}ifa=b{}

Branch

switchstr{    case"a":    case"b":    default:}

Cycle

whilei<10{    i=i+1;}fori0...3{   print(i)}fori=0;i<3;++i{   print(i)}

Function

func hello(name:String)->String{   return"Hello \(name)"}

function allows nesting

Swift Learning notes a basic data type and simple statement syntax