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.

NaN通常用于表示数学运算无法产生有意义的结果的情况，例如0除以0或对负数求平方根等。 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。

Apr 16, 2010 · 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 …

Dec 14, 2019 · In computing, NaN, standing for not a number, is a member of a numeric data type that can be interpreted as a value that is undefined or unrepresentable, especially in floating-point arithmetic. Systematic use of NaNs was introduced by the IEEE 754 floating-point standard in 1985, along with the representation of other non-finite quantities ...

Jul 13, 2023 · 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:

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 ...

Apr 11, 2010 · if NaN is the input of a floating operation, the output also tends to be NaN. there are several possible values for NaN 0x7fc00000, 0x7fc00001, 0x7fc00002, although x86_64 seems to generate only 0x7fc00000. NaN and infinity have similar binary representation. Let's break down a few of them:

Jul 9, 2013 · 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.

Jul 24, 2013 · Different operating systems and programming languages may have different string representations of NaN: nan NaN NaN% NAN NaNQ NaNS qNaN sNaN 1.#SNAN 1.#QNAN -1.#IND I think having all three is just a convenience. They are the same. >>> np.nan nan >>> np.NaN nan >>> np.NAN nan >>>

Dec 18, 2009 · NAN may or may not be defined, and "is defined if and only if the implementation supports quiet NaNs for the float type. It expands to a constant expression of type float representing a quiet NaN." Note that if you're comparing floating point values, and do: a = NAN; even then, a == NAN; is false. One way to check for NaN would be: