在 JavaScript 中，为什么零除以零返回 NaN，而其他除以零返回无穷大? [英] In JavaScript, why does zero divided by zero return NaN, but any other divided by zero return Infinity?

问题描述

在我看来，代码

console.log(1 / 0)

应该返回NaN，但它返回Infinity.但是这段代码:

should return NaN, but instead it returns Infinity. However this code:

console.log(0 / 0)

确实返回NaN.有人可以帮助我理解此功能的原因吗?不仅看起来不一致，而且似乎是错误的，比如x/0 where x !== 0

does return NaN. Can someone help me to understand the reasoning for this functionality? Not only does it seem to be inconsistent, it also seems to be wrong, in the case of x / 0 where x !== 0

推荐答案

因为浮点数就是这样定义的(比 Javascript 更普遍).参见示例:

Because that's how floating-point is defined (more generally than just Javascript). See for example:

• http://en.wikipedia.org/wiki/Floating-point#Infinities
• http://en.wikipedia.org/wiki/NaN#Creation

粗略地说，您可以将 1/0 视为 1/x 的极限，因为 x 趋于零(从右侧开始).并且 0/0 根本没有合理的解释，因此是 NaN.

Crudely speaking, you could think of 1/0 as the limit of 1/x as x tends to zero (from the right). And 0/0 has no reasonable interpretation at all, hence NaN.

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