在swift中使开关大小写不敏感。

Question

我做了一个简单的方法，让用户输入控制台来选择几个选项。

print("Y / N / SUBS / SCENES")
let chooseWisely = readLine()

switch chooseWisely{
  case "Y","ye","yup","yes","y","YES","Yeah","yeya","YES!","Yes","Yup","Both","both":
    print(Alrighty, doing both)

  case "subs", "just subs", "only subs", "subs only", "Subs", "subywuby", "subway", "SUBS":
    print("okay, just subs")

  case "scenes", "Scenes", "shits", "sceneeruskies", "just scenes", "scenes only", "only scenes", "scenes fired", "scenes!", "SCENES", "gimmeh the scenes":
    print("okay, just scenes")

  case .some(_):
    print("Alrighty then, not doing it.")

  case .none:
    print("Alrighty then, not doing it.")
}

正如你所看到的那样，为了覆盖大量可能的用户输入，大小写变得相当繁琐，我至少想通过使其不区分大小写来简化它。

如果我从一开始就走错了路，我也愿意接受一个完全不同的处理用户输入的方法。

Answer 1

先处理标签（比较符）。之前 的比较，使其符合你愿意接受的。例如：

let chooseWisely = // whatever
switch chooseWisely.lowercased() {
case "ye", "yup", "yes", "y", "yeah", "yeya", "yes!", "both" :
    // ... and so on

这符合... yes, YES, Yes，等等。- 再进一步。例如，如果你愿意接受 "是的！"和 "是的"，就把标点符号去掉。chooseWisely 之前 的比较。例如："是的！"匹配 "是的"。

func trimNonalphas(_ s: String) -> String {
    return s.trimmingCharacters(in: CharacterSet.alphanumerics.inverted)
}

switch trimNonalphas(chooseWisely.lowercased()) { // ...

现在 "是的！"匹配 "是的"，以此类推。