Switch 中的模式匹配
Switch 中的模式匹配也很常用，在 Switch 中合理地使用模式匹配可以为我们带来很多好处，可以使我们的代码更简洁，同时可以减少代码量和增加开发效率。
区间匹配
let value = 188
switch value {
case 0..<50:
print("The value is in range [0, 50)")
case 50..<100:
print("The value is in range [50, 100)")
case 100..<150:
print("The value is in range [100, 150)")
case 150..<200:
print("The value is in range [150, 200)")
case 200...:
print("The value is in range [200, ")
default: break
}
// The value is in range [150, 200)
匹配元组类型
创建一个元组类型：
let tuples: (Int, String) = (httpCode: 404, status: "Not Found.")
进行匹配：
switch tuples {
case (400..., let status):
print("The http code is 40x, http status is (status)")
default: break
}
创建一个点：
let somePoint = (1, 1)
进行匹配：
switch somePoint {
case (0, 0):
print("(somePoint) is at the origin")
case (_, 0):
print("(somePoint) is on the x-axis")
case (0, _):
print("(somePoint) is on the y-axis")
case (-2...2, -2...2):
print("(somePoint) is inside the box")
default:
print("(somePoint) is outside of the box")
}
如上，我们在匹配的时候可以使用下划线 _ 对值进行忽略：
switch tuples {
case (404, _):
print("The http code is 404 not found.")
default: break
}
