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- 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
- How do you check that a number is NaN in JavaScript?
NaN === NaN; false Number NaN === NaN; false isNaN(NaN); true isNaN(Number NaN); true Equality operator (== and ===) cannot be used to test a value against NaN Look at Mozilla Documentation The global NaN property is a value representing Not-A-Numbe
- 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。
- python - How to check for NaN values - Stack Overflow
A NaN implemented following the standard, is the only value for which the inequality comparison with itself should return True: def is_nan(x): return (x != x) And some examples: import numpy as np values = [float('nan'), np nan, 55, "string", lambda x : x] for value in values: print(f"{repr(value):<8} : {is_nan(value)}") Output:
- javascript - Why is NaN === NaN false? - Stack Overflow
Why does NaN === NaN return false in Javascript? > undefined === undefined true > NaN === NaN false > a = NaN NaN > a === a false On the documentation page I see this: Testing against NaN Equality operator (== and ===) cannot be used to test a value against NaN Use isNaN instead Is there any reference that answers to the question? It would
- What is the difference between Null, NaN and undefined in JavaScript . . .
A bit more informally and concisely NaN - "not a valid number" usually after you did some operation that should produce one but couldn't undefined - it exists but hasn't been given a value yet null - it exists and it has deliberately been given an empty value That's sort of the idea behind them - basically three different signifiers for "non
- 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
- python - pd. NA vs np. nan for pandas - Stack Overflow
Difference between np nan and pd NA incase of numerical columns : If you use np nan for a integer column, it will convert the datatype of the column to float as np nan is a floating value If you use np nan for a integer column, it doesn't convert the datatype fo the column to float
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