Swift基础学习2

1.数组的创建及操作

//数组
var array=[2,3,4,5]

var array1:Array=[2,4]

var array2:Array<Int>=[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=[5,1]
//升序排序
tempArray.sortInPlace()
print(tempArray)

//数组的批量操作
var array10=[1,5]
array10[0...2]=[10,101,10,10]
等价于
array10.replaceRange(Range(start: 0,end: 3),with: [9,9,9])
array10+=[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([1,5])


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
}