nan
Can an integer be NaN in C++?
No, NaN is a floating point value. Every possible value of an int is a number. Edit The standard says: 6.2.6.2 40) Some combinations of padding bits might generate trap representations, for example, if one padding bit is a parity bit. Regardless, no arithmetic operation on valid values can generate a trap representation other than … Read more
Determine if NSNumber is NaN
So, I found out that the class property [NSDecimalNumber notANumber] is just for this purpose. In some languages NaN != NaN, but this isn’t the case in Cocoa.
Numpy – Replace a number with NaN
A[A==NDV]=numpy.nan A==NDV will produce a boolean array that can be used as an index for A
Are the bit patterns of NaNs really hardware-dependent?
This is what ยง2.3.2 of the JVM 7 spec has to say about it: The elements of the double value set are exactly the values that can be represented using the double floating-point format defined in the IEEE 754 standard, except that there is only one NaN value (IEEE 754 specifies 253-2 distinct NaN values). … Read more
Remove NaN/NULL columns in a Pandas dataframe?
Yes, dropna. See http://pandas.pydata.org/pandas-docs/stable/missing_data.html and the DataFrame.dropna docstring: Definition: DataFrame.dropna(self, axis=0, how=’any’, thresh=None, subset=None) Docstring: Return object with labels on given axis omitted where alternately any or all of the data are missing Parameters ———- axis : {0, 1} how : {‘any’, ‘all’} any : if any NA values are present, drop that label all … Read more
Assigning a variable NaN in python without numpy
Yes — use math.nan. >>> from math import nan >>> print(nan) nan >>> print(nan + 2) nan >>> nan == nan False >>> import math >>> math.isnan(nan) True Before Python 3.5, one could use float(“nan”) (case insensitive). Note that checking to see if two things that are NaN are equal to one another will always … Read more
Sum numbers returns NaN
You didn’t initialize sumNumbers, so you get undefined + a number = NaN var numbers, sumNumbers = 0;
Is NaN a valid key value for associative containers?
They are both forbidden by the standard. For the (ordered) associative containers, the definition of strict weak order (25.4/4) says: If we define equiv(a, b) as !comp(a, b) && !comp(b, a), then the requirements are that comp and equiv both be transitive relations … equiv(a, b) && equiv(b, c) implies equiv(a, c) This fails for … Read more
Why JavaScript says that a number is not a number? [duplicate]
As I understand it, NaN is a sentinel instance of the Number class that represents, well, exactly what it stands for – numeric results that cannot be adequately represented. So 0/0 is not a number, in the sense that it’s NaN, but it is a Number in terms of its type. Perhaps it should have … Read more