遍历枚举值 [英] looping through enum values

问题描述

是否可以在 Objective-C 中循环遍历枚举值?

Is it possible to loop through enum values in Objective-C?

推荐答案

Given

enum Foo {Bar=0,Baz,...,Last};

您可以迭代元素，例如:

you can iterate the elements like:

for(int i=Bar; i<=Last; i++) {
  ...
}

请注意，这暴露了 C 枚举的真正简单的性质.特别是，您可以看到 C 枚举并没有真正提供类型安全，因为您可以使用 int 代替枚举值，反之亦然.此外，这取决于枚举值的声明顺序:至少可以说是脆弱的.另外，请看查克的评论；如果枚举项不连续(例如，因为您为某些项指定了显式的、非连续的值)，则这根本不起作用.哎呀.

Note that this exposes the really-just-an-int nature of a C enum. In particular, you can see that a C enum doesn't really provide type safety, as you can use an int in place of an enum value and vice versa. In addition, this depends on the declaration order of the enum values: fragile to say the least. In addition, please see Chuck's comment; if the enum items are non-contiguous (e.g. because you specified explicit, non-sequential values for some items), this won't work at all. Yikes.

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