sw i f t 作为苹果新的开发语言，相比Object-C相对好理解，项目需要因此需要学习一下，特此写下此笔记
Swift 学习建议参考苹果开发者中心文档：
代码：
//
// main.swift
// swiftlearn
//
// Created by YoungStream on 16/3/23.
// Copyright © 2016年 mugutu. All rights reserved.
//
import Foundation
print("Hello, World!")
//定义变量
var myVar = 42
myVar = 35
var myVar2: Double = 30.345
var myStr:String = "Hello Swift!"
//定义一个常量,没有指明类型时，编译器根据初始值自动推断出myConst是一个整数
let myConst = 43
//定义一个常量并声明类型
let myConst2: Double = 30.0
let myFloat: Float = 4.0
// Int8整型常量或者变量能够存储的数值是-128到127，而UInt8整型常量或者变量能够存储的
//数值范围是0到255.当编译的时候，数值越界是不会自动得到合适的值的，而且会编译出错。
//let t1: UInt8 = -1
/*
整型雨浮点类型的转换
*/
let three = 3
// 转换three为整型
let pi = Double(three) + 0.14569
let integer = Int(3.1415926)
print("This A Value : "+String(integer))
//array数组
var shoppingList = ["one","two","three"]
shoppingList[0] = "once again"
var occupations = [
"one" :"Mom",
"two" :"Lily",
"three" :"Tom"
]
occupations["four"] = "Jack";
//初始化空数组
let emptyArray = [String]()
//初始化空字典
let emptyDictionary = [String:Float]()
//==Control Flow== 流程控制 if else for
let individualScores = [75,43,103,87,12]
var tempScore = 0;
for score in individualScores {
if score > 50 {
tempScore += 3;
} else {
tempScore += 1;
}
}
var optionalString:String? = "Hello"
print(optionalString == nil)
var optionName:String? = nil
//var optionName:String? = "John Appleseed"
var greeting = "Hello!"
if let name = optionName {
greeting = "Hello, \(name)"
} else {
greeting = "Hello,YoungStream"
}
print(greeting)
let nickName: String? = nil
let fullName: String = "Young Stream"
let informalGreeting = "Hi \(nickName ?? fullName)"
print("infomalGreeting : "+informalGreeting)
//Switch Case
let vegetable = "red pepper"
switch vegetable {
case "celery":
print("This is celelry")
case "cucumber","watercress":
print("That would make a good tea sandwich.")
case let x where x.hasSuffix("pepper"):
print("It is a spicy \(x)?")
default:
print("Swicth Case Default Print")
}
//for each pai value
let interestingNumbers = [
"Prime": [2,3,5,7,11,13],
"Fibonacci": [1,1,2,3,5,8],
"Square":[1,4,9,16,25]
]
var largest = 0
for(kind,numbers) in interestingNumbers {
for number in numbers {
if number > largest {
largest = number
}
}
print("key : "+kind)
}
print("The Max Value : "+String(largest))
//While Repeat
var n = 2
while n < 100 {
n = n * 2
}
print("While N Value : "+String(n))
var m = 2
repeat {
m = m * 4
} while m < 100
print("Repeat M Value : "+String(m))
var total = 0
for i in 0..<4 {
total += i
}
print("For ..< Value : "+String(total))
//== Functions and Closures ==
print("=== Functions and Closures ===")
//func FunctionName(paramName:paramType ...) -> returnType {Function Body}
func greet(name:String,day:String) ->String {
return "Hello \(name), today is \(day)."
}
print("Function greet return Value: "+greet("Bob",day:"Tuesday"))
//使用元组返回多个值
func calculateStatistics(scores:[Int]) -> (min: Int,max: Int,sum: Int) {
var min = scores[0]
var max = scores[0]
var sum = 0
for score in scores {
if score > max {
max = score
} else if score < min {
min = score
}
sum += score
}
return (min,max,sum)
}
var calcuReturn = calculateStatistics([1,2,3,4,5,6,7,8,9,10])
print("Function calculateStatistics return Value : max => "+String(calcuReturn.max)+", min => "+String(calcuReturn.0)+", sum => "+String(calcuReturn.sum))
//函数嵌套 Function Nested
func returnFifteen() -> Int {
var y = 10
func add() {
y += 5
}
add()
return y
}
print("Function Nested At. returnFifteen Return Value : "+String(returnFifteen()))
//Function Return Another Function
func makeIncrementer() -> ((Int) -> Int) {
func addOne(number:Int) -> Int {
return 1 + number
}
return addOne
}
var increment = makeIncrementer()
print("Return Function's Return Value : "+String(increment(7)))
//Function use Another Function as Parameter 函数使用应一个函数作为参数
func hasAnyMatches(list:[Int],condition:(Int) ->Bool) -> Bool {
for item in list {
if condition(item) {
return true
}
}
return false
}
func lessThanTen(number:Int) -> Bool {
return number < 10
}
var numbers = [20,19,18,12]
print("Function hasAnyMatches Return Value : "+String(hasAnyMatches(numbers,condition:lessThanTen)))
numbers.map({
(number:Int) -> Int in
let result = 3 * number
return result
})
let sortedNumbers = numbers.sort{$0 > $1}
print("Closures Sorted Numbers Result[闭包函数SortedNumbers结果]")
print(sortedNumbers)
let mappedNumbers = numbers.map({number in 3 * number})
print("Numbers Map Result : "+String(mappedNumbers))
print("Add Total : "+String(tempScore))
print(occupations[shoppingList[1]])
print("Hello Swift :\(myVar) , \(myStr), \(myConst),\(integer)")
//Objects and Classes
class Shape {
var numberOfSides = 0
func simpleDescription() -> String {
return "A shape with \(numberOfSides) sides"
}
}
var shape = Shape()
shape.numberOfSides = 7
var shapeDescription = shape.simpleDescription()
print("Shape Instance Description : "+shapeDescription)
class NamedShape {
var numberOfSides: Int = 0
var name: String
init(name:String) {
self.name = name;
}
func simpleDescription() -> String {
return "A shape with \(numberOfSides) sides."
}
}
class Square: NamedShape {
var sideLength:Double
init(sideLength:Double,name:String) {
self.sideLength = sideLength
super.init(name:name)
numberOfSides = 4
}
func area() -> Double {
return sideLength * sideLength
}
override func simpleDescription() -> String {
return "A square sides of length \(sideLength)."
}
}
let test = Square(sideLength:5.2,name:"my test square")
test.area()
test.simpleDescription()
class EquilateralTriangle: NamedShape {
var sideLength: Double = 0.0
init(sideLength: Double,name: String) {
self.sideLength = sideLength
super.init(name:name)
numberOfSides = 3
}
var perimeter: Double {
get {
return 3.0 * sideLength
}
set {
sideLength = newValue / 3.0
}
}
override func simpleDescription() -> String {
return "An equilateral triangle with sides of length \(sideLength)."
}
}
var triangle = EquilateralTriangle(sideLength: 3.1, name: "a triangle")
print(triangle.perimeter)
triangle.perimeter = 9.9
print(triangle.sideLength)