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- NaN是什么 NaN == NaN 的结果是什么?为什么? - 知乎
NaN与任何其他值（包括NaN本身）进行比较的结果都是false，包括NaN == NaN。 这是因为NaN被定义为不等于任何其他值，甚至不等于它自己。 这是由于NaN的特殊性质导致的。 NaN的比较结果为false的原因是为了遵循IEEE 754浮点数标准，该标准规定了浮点数的比较方式。
- floating point - Why is NaN not equal to NaN? - Stack Overflow
NaN is designed to propagate through all calculations, infecting them like a virus, so if somewhere in your deep, complex calculations you hit upon a NaN, you don't bubble out a seemingly sensible answer Otherwise by identity NaN NaN should equal 1, along with all the other consequences like (NaN NaN)==1, (NaN*1)==NaN, etc
- python - How to check for NaN values - Stack Overflow
float('nan') represents NaN (not a number) But how do I check for it?
- How do you check that a number is NaN in JavaScript?
182 I just came across this technique in the book Effective JavaScript that is pretty simple: Since NaN is the only JavaScript value that is treated as unequal to itself, you can always test if a value is NaN by checking it for equality to itself:
- javascript - Why is NaN === NaN false? - Stack Overflow
JavaScript automatic type conversion convert NaN into number, so checking if a number is not a number will always b false and NaN !== NaN will be true
- What is the difference between NaN and NA? - Cross Validated
I would like to know why some languages like R has both NA and NaN What are the differences or are they equally the same? Is it really needed to have NA?
- python - What is inf and nan? - Stack Overflow
nan stands for Not A Number, and this is not equal to 0 Although positive and negative infinity can be said to be symmetric about 0, the same can be said for any value n, meaning that the result of adding the two yields nan This idea is discussed in this math se question
- What is the difference between NaN and None? - Stack Overflow
NaN can be used as a numerical value on mathematical operations, while None cannot (or at least shouldn't) NaN is a numeric value, as defined in IEEE 754 floating-point standard None is an internal Python type (NoneType) and would be more like "inexistent" or "empty" than "numerically invalid" in this context The main "symptom" of that is that, if you perform, say, an average or a sum on an
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