由网友(幸福。ー半阳光，ー半受伤)分享简介：（乔恩斯基特今日报道的来源）认为：Math.Max(1f, float.NaN) == NaNnew[] { 1f, float.NaN }.Max() == 1f为什么？编辑：用双也是同样的问题。same issue with double also!推荐答案正如其他已经公布，我啾啾的一个的那种为什么 -...

（乔恩斯基特今日报道的来源）认为：

Math.Max(1f, float.NaN) == NaN
new[] { 1f, float.NaN }.Max() == 1f

为什么？

编辑：用双也是同样的问题。

same issue with double also!

推荐答案

正如其他已经公布，我啾啾的一个的那种为什么 - 在它使用 IComparable的的记录。

As others have posted, I tweeted one sort of "why" - in that it's using IComparable as documented.

这只是导致了另一个为什么虽然。特别是：

That just leads to another "why" though. In particular:

Console.WriteLine(Math.Max(0, float.NaN));  // Prints NaN
Console.WriteLine(0f.CompareTo(float.NaN)); // Prints 1

的第一行表明，NaN被认为是大于0的第二行表明，0被认为是大于NaN的。 （这些都不可以报告这种比较是没有意义的，当然，结果。）

The first line suggests that NaN is regarded as being greater than 0. The second line suggests that 0 is regarded as being greater than NaN. (Neither of these can report the result of "this comparison doesn't make sense", of course.)

我看到所有的答复鸣叫，当然也包括这些 2 ：

I have the advantage of seeing all the reply tweets, of course, including these two:

这似乎是不寻常的，但是这是正确的答案。数组MAX（）是NaN当且仅当所有的元素都为NaN。见IEEE 754R。

It may seem unusual, but that's the right answer. max() of an array is NaN iff all elements are NaN. See IEEE 754r.

此外，Math.Max​​使用IEEE 754R整体排序predicate，它指定为NaN与他人的相对排序。

Also, Math.Max uses IEEE 754r total ordering predicate, which specifies relative ordering of NaN vs. others.