Swift 数组,字典,集合-Array,Set,Dictionary(二)

https://github.com/Zhangjingwang1993/Swift.git

Swift 语言提供Arrays、Sets和Dictionaries三种基本的集合类型用来存储集合数据。数组（Arrays）是有序数据的集。集合（Sets）是无序无重复数据的集。字典（Dictionaries）是无序的键值对的集

可变数组

var someInts = [Int]() // 空数组
var genders1:[String] = ["boy","girl"];// 字符数组
var numbers = [1,2,3,4,5] // 整型数组

不可变数组

let genders = ["male","female"]

数组元素的个数和访问数组元素

print("numbers 数组的长度: \(numbers.count) 数组的第一个值:\(numbers[0])")

追加数组元素

numbers.append(6)
print("numbers 数组的长度: \(numbers.count) 数组的第一个值:\(numbers[5])")// 6 6
// 使用加法赋值运算符(+=) 也可以在数组后面添加数组
genders1+=["ios"]
print("numbers 数组:\(genders1)") // 运行结果 : numbers 数组:["boy","girl","ios"]

在某个位置插入元素,Swift 点语法

genders1.insert("Objective-C",atIndex: 2)
print("numbers 数组:\(genders1)") // 运行结果 : numbers 数组:["boy","girl","Objective-C","ios"]

删除元素

genders1.removeAtIndex(2)
print("numbers 数组:\(genders1)") // 运行结果 : numbers 数组:["boy","ios"]

判断数组是否为空

if genders1.isEmpty{
        print("null")
        }

遍历数组

for begin in genders1{
        print(begin)
        }
// 或者
for (index,value) in genders1.enumerate(){
        print("Item \(String(index + 1)): \(value)")
        }

字典的定义

var dic = ["ios":"swfit","coder":"I"]

字典访问 键对应的值

let name = dic["ios"]
print(name) // Optional("swfit")

添加

dic ["boy"] = "Zhang"
print(dic)  // ["boy": "Zhang","coder": "I","ios": "swfit"]

删除

dic.removeValueForKey("boy")
print(dic)  // ["coder": "I","ios": "swfit"]

修改

dic.updateValue("Student",forKey: "coder")
print(dic)  // ["coder": "Student","ios": "swfit"]

遍历字典

for (key,value) in dic{
       print("key:\(key) value:\(value)")
        }
        //或者
for d in dic{
       print("key1:\(d.0) value1:\(d.1)")
        }

单独遍历key 和 value

for key in dic.keys{
        print("Key= \(key)")
        }
for value in dic.values{
        print("value= \(value)")
        }