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- What is NaN (Not a Number) in the words of a beginner?
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
- 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:
- Whats the difference between nan, NaN and NAN - Stack Overflow
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 >>>
- 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。
- 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
- c# - what does NaN mean for doubles? - Stack Overflow
In computing, NaN (Not a Number) is a value of the numeric data type representing an undefined or unrepresentable value, especially in floating-point calculations Systematic use of NaNs was introduced by the IEEE 754 floating-point standard in 1985, along with the representation of other non-finite quantities like infinities
- 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
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