在Python中使用assert的例子？ [英] Example use of assert in Python?

问题描述

我已经阅读了关于何时使用断言与异常，但我还没有得到它。似乎每当我认为我处于使用断言的情况下，后来在开发中，我发现我是在我飞跃之前，以确保在调用该函数时该断言不会失败。由于还有一个Python习惯用于尝试使用try-except，所以我通常最终会断言assert并抛出一个异常。我还没有找到一个似乎使用断言的地方。任何人都可以提出一些很好的例子？

I've read about when to use assert vs. exceptions, but I'm still not "getting it". It seems like whenever I think I'm in a situation where I should use assert, later on in development I find that I'm "looking before I leap" to make sure the assert doesn't fail when I call the function. Since there's another Python idiom about preferring to use try-except, I generally end up ditching the assert and throwing an exception instead. I have yet to find a place where it seems right to use an assert. Can anyone come up with some good examples?

推荐答案

一个很好的指导是使用 assert 它的触发意味着代码中的错误。当你的代码假设某事并采取行动时，建议用断言来保护这个假设。 断言失败意味着您的假设不正确，这意味着您的代码不正确。

A good guideline is using assert when its triggering means a bug in your code. When your code assumes something and acts upon the assumption, it's recommended to protect this assumption with an assert. This assert failing means your assumption isn't correct, which means your code isn't correct.

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