Armin Ronacher firstname.lastname@example.org wrote:
It's one of those "non issues" but there are still some situations where you have to deal with Infinity and NaN, even in Python. Basically one the problems is that the repr of floating point numbers is platform depending and sometimes yields "nan" which is not evaluable. It's true that eval() is probably a bad thing but there are some libraries that use repr/%r for code generation and it could happen that they produce erroneous code because of that. Also there is no way to get the Infinity and NaN values and also no way to test if they exist.
Maybe changing the repr of `nan` to `math.NaN` and `inf` to `math.Infinity` as well as `-inf` to `(-math.Infinity)` and add that code to the math module (of course as a C implementation, there are even macros for testing for NaN values)::
That would work for eval(repr(x)), but it fails for float(repr(x)). I believe this particular issue has been brought up before, as well as the particular solution, but I can't remember the final outcome.
Infinity = 1e10000
Has the storage of infinity in .pyc files been fixed? For a while it was broken.
NaN = Infinity / Infinity def is_nan(x): return type(x) is float and x != x def is_finite(x): return x != Infinity
def is_finite(x): return x not in (Infinity, -Infinity)