what is nan in python code example

Example 1: python3 is nan

>>> import math
>>> x = float('nan')
>>> math.isnan(x)
True

Example 2: NaN stand for python

not a number
NaN , standing for not a number, is a numeric data type used to represent any value that is undefined or unpresentable. For example, 0/0 is undefined as a real number and is, therefore, represented by NaN.