2019年12月14日 · 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 ...

2015年10月28日 · 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:

2013年7月13日 · 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 …

2023年7月13日 · 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:

2013年7月24日 · 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 >>>

2011年11月13日 · Not a Number or NaN is a computational construct, that came along with parsers and programmatic limitations, and its output can be assigned different meaning depending on the function in question. For instance, a result may only be mathematically tractable using a different number system , which is easy for a mathematician to do, but in your ...

so basically NaN,NAN and nan are equivalent definitions of nan or in other words. NaN and NAN are aliases of nan. np.nan np.NaN np.NAN

Infinity and NaN Infinity. MATLAB ® represents infinity by the special value Inf.Infinity results from operations like division by zero and overflow, which lead to results too large to represent as conventional floating-point values.

NaN values in a vector are treated as different unique elements. For example, unique([1 1 NaN NaN]) returns the row vector [1 NaN NaN]. Use the isnan or ismissing function to detect NaN values in an array. Use the anynan or anymissing function to determine if any array element is …

2013年7月9日 · 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.