常量和变量
常量 ：let max = 10 变量声明 var 变量名 : 类型 变量字面量 var index = 4 初始化 var index:NSInteger!
数组
var someInts = [Int]() var someInts[1,2,3] 增 someInts.append(1) someInts.append(2) someInts.append(3) 取： let a = someInts[0] //a = 1 let b = someInts[1] //b = 2 let c = someInts[2] //c = 3 插 someInts.insert(4, at: 0) someInts.insert(5, at: 0) //someInts = [5,4,1,2,3] 删 someInts.remove(at: 0)
字典
var namesOfIntegers = [String: String]() //字面量 var namesOfIntegers = ["a":"1","b":"2","c":"3"] 增 namesOfIntegers["one"] = "1" namesOfIntegers["two"] = "2" namesOfIntegers["three"] = "3" 删 namesOfIntegers["one"] = nil 改 namesOfIntegers["one"] = "hello" 取 let one = nameOfIntegers["one"]
for循环
遍历字典
let names = ["Anna", "Alex", "Brian", "Jack"]
for name in names {
print("Hello, \(name)!")
}
// Hello, Anna!
// Hello, Alex!
// Hello, Brian!
// Hello, Jack!
遍历数组
let numberOfLegs = ["spider": 8, "ant": 6, "cat": 4]
for (animalName, legCount) in numberOfLegs {
print("\(animalName)s have \(legCount) legs")
}
// ants have 6 legs
// spiders have 8 legs
// cats have 4 legs
数字范围
for index in 1...5 {
print("\(index) times 5 is \(index * 5)")
}
// 1 times 5 is 5
// 2 times 5 is 10
// 3 times 5 is 15
// 4 times 5 is 20
// 5 times 5 is 25