float('nan') represents NaN (not a number). But how do I check for it? 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: 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 ... What is a NaN value or NaN exactly (in the words of a non-math professor)?
dr nan jiang houston tx, Let's suppose you're working with real numbers - numbers like 1, π, e, -137, 6.626, etc. In the land of real numbers, there are some operations that usually can be performed, but sometimes don't have a defined result. For example, let's look at logarithms. What is NaN (Not a Number) in the words of a beginner? 16 NaN means "Not a Number" and is the result of undefined operations on floating point numbers like for example dividing zero by zero.
dr nan jiang houston tx, (Note that while dividing a non-zero number by zero is also usually undefined in mathematics, it does not result in NaN but in positive or negative infinity). In numpy there are nan, NaN and NAN. What's the sense of having all three, do they differ or any of these can be used interchangeably? 37 It's a special case, NaN is the only thing in Javascript not equal to itself. Although the other answers about strings vs the NaN object are right too.
