Swift 学习笔记之数组，集合，字典

数组

---

/* 创建数组  */

var arr = Array()

var marr = [String]();

//创建字面量数组

var array : [String] = ["1","2","3","4"]

var array1 : Array = ["1","2","3"]

//数组的数量

array.count

//数组判空

array.isEmpty

/* 增 */

array.append("5")

//增

array += ["6"]

array.insert("7", at: 3)

/* 删 */

array.removeLast()

array.removeFirst()

array.removeAll()

array.remove(at: 0)

/*  改  */

//修改第0个元素的值

array[0] = "modify"

//批量修改下标为1-3的元素的值

array[1...3] = ["a","b","c"]

/*  查  */

for value in array{

    print(value)

}

//根据区间便利数组的元素

for value in array[0..<5]{

    print(value)

}

//通过下标获取数组的元素

var arr = ["a","b","c"]

for i in 0..

    print(i,arr[i])

}

//每个元素以及值的整数索引

for (index ,value) in array.enumerated(){

    print(index,value)

}

集合

---

//创建集合

var set = Set()

//字面量创建

var set1 : Set = ["1" , "a", "2" , "b"]

//数量

set.count

//空判断

set.isEmpty

/*增*/

set.insert("3")

/* 删 */

//移除第一个元素

set.removeFirst()

//移除所有的元素

set.removeAll()

//已知集合中的元素，将其移除

set.remove("1")

//根据下表移除响应的元素

set.remove(at: set.startIndex)

set.remove(at: set.index(set.startIndex, offsetBy: 2))

/* 查 */

//输出无序的集合元素

for value in set {

    print(value)

}

//输出排完序的集合元素

for value in set.sorted(){

    print(value)

}

/*集合的交集和并集*/

var set1 : Set = ["1","2","3","4"]

var set2 : Set = ["3","4","5","6"]

//两个集合的交集

let result = set1.intersection(set2)

/* 输出结果是 "3", "4" */

//两个集合的并集

let result1 = set1.union(set2)

/* 输出结果是 "4", "2", "1", "5", "6", "3" */

字典

---

//创建字典

var dictionary = Dictionary()

var dic1 : Dictionary = ["1":"1","2":"2"]

var dic2 = ["3" : "3" ,"5" : "5"]

//字典中的键值对的数量

dic1.count

//字典中的所有的键

dic1.keys

//字典是否为空

dic1.isEmpty

/*  增 */

dic1["3"] = "3"

dic1["4"] = "4"

/*  删  */

dic1.removeAll()

dic1.removeValue(forKey: "4")

/*  改  */

dic1["4"] = "modify"

dic1.updateValue("newValue", forKey: "3")

/*  查  */

//便利所有的键值对

for value in dic1{

    print(value)

}

//既有键又有值的便利方法

for (key ,value) in dic1{

    print(key,value)

}

//便利所有的键的方法

for key in dic1.keys{

    print(key)

}

//便利所有的值

for value in dic1.values{

    print(value)

}