1.通配符模式
_ 表示可匹配任何值。
？表示匹配非nil值。
例子：
enum Person {
case sutdent(name: String,age: Int?)
case teacher(name: String,age: Int?)
}
func text1(p: Person) {
switch p {
case .sutdent(let name, _):
print("student",name)
case .teacher(let name, _?):
print("teacher",name)
default:
print("other")
}
}
var p1 = Person.sutdent(name: "p1", age: 10)
var p2 = Person.sutdent(name: "p2", age: nil)
var p3 = Person.teacher(name: "p3", age: 20)
var p4 = Person.teacher(name: "p4", age: nil)
text1(p: p1)
text1(p: p2)
text1(p: p3)
text1(p: p4)2.标识符模式
给对应的变量，常量赋值。
3.值绑定模式
let point = (1, 2)
switch point {
case let (x ,y):
print(x,y)
default:
break
}4.元组模式
var scrores = ["A":"100","B":"80","C":"70"]
for (name,scroe) in scrores {
print("name",name,"scroe",scroe)
}5.枚举Case模式
let scroe = 2
if case 0...5 = scroe {
print(scroe)
}6.可选模式
let scroe: Int? = 2
if case let x? = scroe {
print(x)
}7.类型转换模式
class Animal {
func eat() {print(type(of: self),"eat")}
}
class Dog: Animal {
func run(){print("Dog run")}
}
class Cat: Animal {
func jump(){print("Cat jump")}
}
func cheak(animal: Animal) {
switch animal {
case let dog as Dog:
dog.eat()
dog.run()
case is Cat:
animal.eat()
default:
break
}
}
cheak(animal: Dog())
cheak(animal: Cat())
8.表达式模式
let point = (1, 2)
switch point {
case (0, 0):
print("0 , 0")
case (1...3, 2...5):
print(point.0, point.1)
default:
print("other")
}9.where
使用where为模式匹配增加匹配条件。
let point = (1, 2)
switch point {
case let (x, y) where x > 0 && y > 0:
print(x,y)
default:
print("other")
}
