Swift学习之基本语法

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我是靠谱客的博主动听衬衫，最近开发中收集的这篇文章主要介绍Swift学习之基本语法，觉得挺不错的，现在分享给大家，希望可以做个参考。

概述

1.数组的创建及操作

//数组
var array=[2,3,4,5]
var array1:Array=[2,3,3,4]
var array2:Array<Int>=[2,2,2,3]
var array3:[Int]=[2,3]
var array4:[Double]=[2.2,3.3]
var array5:[String]=["333"]
var array6:Array<Any>=["2",2]
var array7=["33",3]
//追加元素
array7.append("d")
//插入元素
array7.insert("hhhh", atIndex: 0)
//删除最后一个元素
array7.removeLast()
//删除指定下标的元素
array7.removeAtIndex(0)
//只删除数组中的值，保存数组的容量
array7.removeAll(keepCapacity: true)
print(array7)
print(array7.capacity)
print(array7)
for vale in array7{
print(vale)
}
var tempArray=[5,4,3,2,1]
//升序排序
tempArray.sortInPlace()
print(tempArray)
//数组的批量操作
var array10=[1,2,3,4,5]
array10[0...2]=[10,101,10,10]
等价于
array10.replaceRange(Range(start: 0, end: 3), with: [9,9,9,9])
array10+=[1,1,1,1]
array10+=array10
print(array10)
//遍历数组
for elm in array10{
print(elm)
}
for (index,value) in array10.enumerate(){
print("index:(index)==(value)")
}

2.Range的创建

var range:Range<Int>=Range(start: 0, end: 5)
var range1=0...5
var range2=0..<5
print(range)
print(range1)
print(range2)

3.Dictionary的创建及操作

var dict:Dictionary<String,String>=["2":"2"];
var dict2=["2":2,"3":3]
for (key,value) in dict2{
print("key==(key),value=(value)")
}
//遍历字典所有的key
for key in dict2.keys{
print(key)
}
//遍历字典所有的value
for value in dict2.values{
print(value)
}
----------
var dict=["app":"苹果","ban":"香蕉"]
dict["app"]="菠萝"
//如果key不存在，此方法会把新key和新值加入dict
if let orig=dict.updateValue("苹果", forKey: "app"){
//存在当前key，改变后的值
print(dict["app"])
//存在当前key，改变前的值
print(orig)
}
//根据key删除对应的值
dict.removeValueForKey("app")
print(dict)
dict["an"]="一个"
//根据key删除元素，若key不存在，此方法把新key和新值加入dict
if let old=dict.removeValueForKey("and"){
print(old)
}

4.func

//函数
func showIntArray(array:[Int]){
for a in array{
print(a)
}
}
showIntArray([1,2,3,4,5])
func maxOfValue(num1 a:Int,num2 b:Int)->Int{
return a>b ? a : b
}
print(maxOfValue(num1: 9, num2: 20))
let p0:(Double,Double)=(0,0)
let p1:(Double,Double)=(6,6)
func getLengthAndWidth(p0:(Double,Double),p1:(Double,Double))->(legnth:Double,width:Double){
return (abs(p0.1-p1.1),abs(p0.0-p1.0))
}
print(getLengthAndWidth(p0, p1: p1
).legnth)
func divisionOperation(dividend dividend:Double,divisor:Double)->Double{
return dividend/divisor
}
divisionOperation(dividend: 3.3, divisor: 3)

5.闭包

//闭包
let sayhello={
print("hello")
}
sayhello()
let add:(Int,Int)->Int={
(a:Int,b:Int)->Int in
return a+b
}
// 利用闭包实现冒泡排序
1.第1种写法
func show(array:[Int]){
for x in array
{
print("(x)");
}
}
func arrSort(inout array:[Int],cmp:(Int ,Int)->Int){
let
cnt = array.count
for var i=1; i<cnt ; i++ {
for var j=0; j<cnt-i; j++ {
if(cmp(array[j],array[j+1]) == -1){
let t=array[j];
array[j]=array[j+1]
array[j+1]=t
}
}
}
}
var array=[20,2,3,70,8]
show(array)
let intCmp={
(a:Int,b:Int)->Int in
if a>b{
return -1
}
else if a<b{
return 1
}
else{
return 0
}
}
arrSort(&array,cmp: intCmp)
show(array)
//第2种写法
arrSort(&array,cmp: {
(a:Int,b:Int)->Int in
if a>b{
return -1
}
else if a<b{
return 1
}
else{
return 0
}
})
// 第3种方法
arrSort(&array,cmp: {
(a,b) in
if a>b{
return -1
}
else if a<b{
return 1
}
else{
return 0
}
})
// 第4种方法
arrSort(&array,cmp: {
let a=$0,b=$1
if a>b{
return -1
}
else if a<b {
return 1
}
else{
return 0
}
})
----------
//尾随闭包
var array=[20,2,3,70,8]
array.sortInPlace()//默认升序
//降序
array.sortInPlace({
return $0 > $1
})
//升序
array.sortInPlace(){
return $0 > $1
}
show(array)

6.嵌套函数

//函数嵌套
func swap( var intout a : Int ,var intout b : Int){
let t=a
a = b
b = t
}
func arrSort(inout array:[Int]){
//func swap( var intout a : Int ,var intout b : Int){
//let t=a
//a = b
//
b = t
//}
let
cnt = array.count
for var i=1; i<cnt ; i++ {
for var j=0; j<cnt-i; j++ {
if((array[j]>array[j+1])){
swap(&array[j], &array[j+1])
}
}
}
}
var array=[20,2,3,70,8]
arrSort(&array)
show(array)

7.枚举

//枚举
enum Method:Int{
//
case Add
//
case Sub
//
case Mul
//
case Div
case Add = 5,Sub = 6,Mul = 7,Div = 8
}
var value0:Method = .Add
var value1 = Method.Sub
func seleMethod(op: Method)->(Double,Double)->Double{
switch op{
case .Add:
func add(a:Double,b:Double)->Double{
return a + b
}
return add
case .Sub:
func sub(a:Double,b:Double)->Double{
return a-b
}
return sub
case .Mul:
return {return $0 * $1}
case .Div:
return {$0 / $1}
}
}
let mehtod = seleMethod(Method.Add)
print(mehtod(4.0,5.0))
print(seleMethod(.Add)(5.0,7.0))
print(Method.Add.rawValue)
enum MethodStr:String{
case Add = "ss",Sub = "sss",Mul = "ssss",Div = "sssss"
}
print(MethodStr(rawValue: "Add"))
//关联值
enum LineSegmentDescriptor{
case StartAndEndPattern(start:Double,end:Double)
case StartAndLengthPattern(start:Double,length:Double)
}
var
lsd=LineSegmentDescriptor.StartAndEndPattern(start: 10, end: 30)
lsd=LineSegmentDescriptor.StartAndEndPattern(start: 10, end: 30)
switch lsd{
case .StartAndEndPattern(let s,let e):
print("(s)->(e)")
case .StartAndLengthPattern(let s,let len):
print("(s)->(len)")
}

8.结构体

//结构体
//例子1
struct Rect{
var width:Double=0.0
var height:Double=0.0
}
//不带参数的构造
var rect:Rect = Rect()
rect.width=100
rect.height=100
print(rect.width)
print(rect.height)
//函数体逐一构造器，1、需要按照顺序，2、所有成员变量都必须构造
var rect1:Rect = Rect(width: 20, height: 30)
print(rect1)
//例子2
struct Rect{
var width:Double=0.0
var height:Double=0.0
//成员方法可以访问使用成员变量
func getWith()->Double{
return width
}
func show(){
print("width=(width),height=(height)")
}
}
//例子3
struct myRect{
var origion:(x:Double,y:Double)=(0,0)
var size:(w:Double,h:Double)=(0,0)
//计算属性
var center:(x:Double,y:Double){
get{
return (origion.x + size.w/2,origion.y + size.h/2)
}
set(n){
//计算属性不能被赋值
origion.x=n.x - size.w/2
origion.y=n.y - size.h/2
}
}
}
var rect = myRect()
rect.origion=(10,10)
rect.size=(20,20)
print("center;=(rect.center)")
struct myRect1{
var origion:(x:Double,y:Double)=(0,0)
var size:(w:Double,h:Double)=(0,0)
//计算属性
var center:(x:Double,y:Double){
get{
return (origion.x + size.w/2,origion.y + size.h/2)
}
set{
//计算属性不能被赋值,系统默认的setter值
origion.x=newValue.x - size.w/2
origion.y=newValue.y - size.h/2
}
}
}