问题描述
我相信我理解为什么选项很方便（我最好的想法是能够返回一个nil布尔值），但在什么情况下我想声明一个包装的可选用？而不是 ！对于隐式展开的可选项。
I believe I understand why optionals are handy (my best thought for use is to be able to return a nil Boolean value), but in what case would I want to declare a wrapped optional using ? rather than ! for an implicitly unwrapped optional.
似乎没有必要用它来声明它？然后必须打字！到处都是，而不仅仅是使用！一次。
It just seems unnecessary to declare it with ? and then have to type ! all over the place rather than just using ! once.
我不想忽视？虽然没用，但我找不到它的用途...任何想法？
I don't want to disregard the ? as useless, but I just can't find a use for it... Any ideas?
推荐答案
如果你试图访问隐式展开的可选项的内容，并且没有任何内容，您的应用程序将崩溃。
If you try to access the content of an implicitly unwrapped optional and there's nothing there, your app will crash.
如果您使用模式检查可选内容 - 例如 - 您可以控制应用程序在不可预见的情况下如何正常失败。并且它不会使你的代码变得更加复杂。
If you use the patterns for checking the content of an optional — like optional binding and optional chaining - you can control how your app should fail gracefully in unforeseen situations. And it doesn't make your code all that more complicated.
不崩溃对我来说似乎是一个很好的理由。
Not crashing seems like a good reason to me.
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