print(places)
//输出
/*
把南京插入到索引为3的位置
["beijing", "shanghai", "guangzhou", "nanjing", "shenzhen", "dezhou", "NewYork", "london", "Sao paolu"]
*/
//4??.5移除
places.remove(at: 3)
print(places)
/*
输出结果 少了索引为3的 nanjing 输出成功
["beijing", "shanghai", "guangzhou", "shenzhen", "dezhou", "NewYork", "london", "Sao paolu"]
*/
//1??
let cardno : Set = [1,2,3,4,5,1,2,3,4]
print(cardno)
//输出[2, 4, 5, 3, 1]
//2??用数组字面量创建集合
var citys : Set = ["shanghai","beijing","dezhou","shanghai","beijing","dezhou"]
//2??.1元素计数：count ，空否 ：isEmpty
print("元素\(citys.count)个，是否为空：\(citys.isEmpty)")
//输出： 元素3个，是否为空：false 去除重复元素只计数 非重复的元素的个数
//2??.2插入: insert
citys.insert("nanjing")
print(citys)
//输出["shanghai", "dezhou", "nanjing", "beijing"]
//2??.3移除
citys.remove("shanghai")
print(citys)//["dezhou", "nanjing", "beijing"]
//2??.4是否包含元素：contains
print(citys.contains("dezhou"))//输出 true
//2??.5 转换为数组：sorted
let citysArray = citys.sorted()
print(citysArray)//["beijing", "dezhou", "nanjing"]
//3??.1 交集 找出两个集合相同的元素
let srray = ["nanjing"]
【北京的雾霾为什么没了 wumai】let arys = citys.intersection(srray)
print(arys)//输出["nanjing"]
//3??.2 差集
let sub = citys.subtracting(arys)
print(sub)//输出["dezhou", "beijing"]
//3??.3并集
let sum = citys.union(sub)
print(sum)//输出["dezhou", "nanjing", "beijing"]
//1??
var dic = ["name":"jack","age":"12","birsday":"1993-09-04"]
print(dic)
//2?? 判断个数 是否为空
print("元素\(dic.count)个数,是否为空\(dic.isEmpty)")//元素3个数,是否为空false
//3??添加或更新元素
dic["shengao"] = "176"
print("添加身高元素之后的dic ==\(dic)")
//输出
/*
添加身高元素之后的dic ==["name": "jack", "age": "12", "birsday": "1993-09-04", "shengao": "176"]
*/
dic["shengao"] = "178"
print("更新身高元素之后的dic ==\(dic)")
//输出
/*
更新身高元素之后的dic ==["name": "jack", "age": "12", "birsday": "1993-09-04", "shengao": "178"]
*/
//获取某项的情况
let shengao : String = dic["shengao"]!
print("身高是\(shengao)")//身高是178
//4??移除，用下表把值设为nil
dic["shengao"] = nil
print(dic)
/*
输出 去除了身高的那一项
["name": "jack", "age": "12", "birsday": "1993-09-04"]
*/
//5??循环一个字典 for in ,因为键值对有2个元素，用元组变量
for (key ,value) in dic {
print(key,value)
}
//输出
/*
name jack
age 12
birsday 1993-09-04
*/
//6??单独使用 键值对里面的keys 或者 values（可使用for in）
for keys in dic.keys{
print(keys)
}
//输出
/*
name
age
birsday
*/
for values in dic.values{
print(values)
}
//输出
/*
jack
12
1993-09-04
*/
//7??把键值对分离成数组，用[数组类型]（字典变量.keys）,[数组类型]（字典变量.values）
let mingcheng = [String](dic.keys)
let qingkuang = [String](dic.values)
print(mingcheng,qingkuang)
/*
输出
["name", "age", "birsday"]
["jack", "12", "1993-09-04"]
*/
//15.1
let places = ["beijing","guangzhou","shenzhen"]
for place in places {
print(place)
}
/*输出
beijing
guangzhou
shenzhen

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