一 數(shù)組
數(shù)組是一堆有序的由相同類型元素構(gòu)成的集合類型
定義
let stuArray : Array<String> = ["zhangsan","18"]
獲取長度
array.count
判空
array.isEmpty
取值
array[1]
array[0...2]
array[0..<2]
array[..2]
array[2..]
array.first
array.last
array.prefix(2)
array.suffix(2)
添加數(shù)據(jù)
array.append("zhouliu")
插入數(shù)據(jù)
array.insert("haojian",at:0)
修改數(shù)據(jù)
array[0] = "wangqi"
刪除數(shù)據(jù)
remove 會改變原數(shù)組的值，返回被刪除的那個元素
drop 不會改變原數(shù)組的值，返回刪除元素后的新數(shù)組
array.remove(at:0)
array.removeFirst()
array.removeLast()
array.removeAll
array.dropFirst()
array.dropLast()
是否包含
array.contains("zhangsan")
倒序
array.reverse
索引
var students = ["zhangsan","Lisi","Wangwu","zhangsan"]
students.firstIndex(of :"zhangsan")
students.lastIndex(of :"zhangsan")
合并
var array = ["zhangsan" , "lisi","wangwu"]
var array1 = ["zhaoliu","wangqi"]
var array2 = array + array1
遍歷
var array = ["zhangsan" , "lisi" , "wangwu"]
for i in 0..< array.count
print(array[i])
}
for item in array {
print(item)
}
for item in array[0..<2]
{
print(item)
}
for (index,name) in array.enumerated() {
print(index)
print(name)
}
var array = ["zhangsan","lisi","wangwu"]
var i = array.makeIterator()
i.next()
i.next()
i.next()
二 集合
與數(shù)組的概念差不多，主要區(qū)別：
元素無序
元素不能重復
let stuSet:Set<String> = ["zhangsan","18"]
數(shù)組轉(zhuǎn)集合
let stuArray = ["zhangsan","18"]
let stuSet = Set(stuArray)
定義空集合
let set: Set<String> = Set()
let set: Set<String> = []
獲取長度
set.count
判空
set.isEmpty
取值
set.first
Set(set.prefix(2))
Set(set.suffix(2))
插入數(shù)據(jù)
set.insert("man")
三 字典
字典是由鍵值對 key:value 對組合的集合類型
字典中的元素之間是無序的
var dict1: Dictionary<String,String> = ["name":"zhangsan","age":"18"]
var dict1: [String : String] = [:]
獲取長度
dict.count
判空
dict.isEmpty
查詢數(shù)據(jù)
dict["name"]
修改數(shù)據(jù)
dict["name"] = "lisi"
刪除數(shù)據(jù)
dict.removeValue(forKey : "height")
合并
var dict1:[String:String] = ["name":"zhangsan","age":"20"]
var dict2:[String:String] = ["height":"1.8","phoneNum":"188888"]
for (key,value) in dict2 {
dict1[key] = value
}
print dict1
遍歷
var dict:[String:String] = ["name" : "zhangsan","age":"18"]
for value in dict.values{
print (value)
}
var dict :[String:String] = ["name":"zhangsan","age":"18"]
for key in dict.keys{
print(key)
}
var dict: [String:String] = ["name":"zhangsan","age":"18"]
for (key,value) in dict{
print("(key) - (value)")
}
枚舉方式遍歷
var dict :[String:String] = ["name":"zhangsan","age":"18"]
for (index,value) in dict.enumerated() {
print("(index) - (value)")
}
迭代器
var dict:[String : String] = ["name":"zhangsan","age":"18"]
var d = dict.makeIterator()
a.next()
a.next()?.value
四 函數(shù)
函數(shù)是由一組語句構(gòu)成的代碼塊，用于完成某個特定的功能呢。
定義與調(diào)用
訪問修飾符 func 函數(shù)名（形式參數(shù)列表） -> 返回值類型 {
代碼塊
return 返回值
}
標簽與名稱
每個函數(shù)的形式參數(shù) 都包含 形式參數(shù)標簽 和形式參數(shù)名稱
可變參數(shù)
for total(numbers: Int...) -> Int{
var sum = 0
for i in numbers{
sum += i
}
return sum
}
total ()
total (numbers : 10)
輸入輸出參數(shù)
func swapInt(a:inout Int ,b: inout Int){
let temp = a
a = b
b = temp
}
var a = 10
var b = 20
SwapInt (a:&a , b:&b)
五 閉包
定義像函數(shù)，單沒有名字
調(diào)用類似函數(shù)，也需要傳參數(shù)
通過查看類型會發(fā)現(xiàn)就是前面講的函數(shù)類型
閉包是一種特殊的沒有名字的函數(shù)
let squareClosure = { (param : Int) -> Int in
return param*param
}
squareClosure(3)
{ (parameters) -> return type in
statements
}
1 來順序調(diào)用閉包的參數(shù)
省略 -> 返回類型
省略 參數(shù)類型和括號
省略 一條執(zhí)行語句時 ，return 關(guān)鍵字省略
參數(shù)名稱縮寫 改為 1
捕獲
var vehicle = "car"
var animal = "Cat"
let closure = { [vehicle] in
print ("Viehichle is (vechicle)")
print ("Animale is (animal)")
}
vehicle = "Airplane"
animale = "Dog"
closure ()
捕獲列表中的 vehicle 是 car 是拷貝類型
animal 是引用類型 ，是 Dog
尾隨閉包
閉包是函數(shù)的最后一個參數(shù)
逃逸閉包
閉包在函數(shù)執(zhí)行完之后再調(diào)用
