很明显swift的switch比oc的功能强化的多 下面是学习参考
<h5>不像 C 语言里的switch语句，在 Swift 中，switch语句不会一起匹配"a"和"A"。相反的，上面的代码会引起编译期错误：case "a": 不包含任何可执行语句——这就避免了意外地从一个 case 分支贯穿到另外一个，使得代码更安全、也更直观。</h5>
先配个图
区间匹配
let countedThings = "moons orbiting Saturn"
var naturalCount: String
switch approximateCount {
case 0:
naturalCount = "no"
case 1..<5:
naturalCount = "a few"
case 5..<12:
naturalCount = "several"
case 12..<100:
naturalCount = "dozens of"
case 100..<1000:
naturalCount = "hundreds of"
default:
naturalCount = "many"
}
print("There are \(naturalCount) \(countedThings).")
// 输出 "There are dozens of moons orbiting Saturn."
