Why aren't the keywords Inf, -Inf, and NaN specified in Python?

Question

In PEP 754, a disclaimer, it stated that:

This PEP is rejected. After sitting for four years, it was not possible to provide sufficient community interest.

For Python 2.6, several ideas for this PEP were implemented. float ('inf') and repr (float ('inf')) are now guaranteed to work with every supported platform with IEEE 754 semantics. However, eval (repr (float ('inf'))) roundtrip is still not supported unless you define inf and nan yourself:

>>> inf = float('inf')
>>> inf, 1E400
(inf, inf)
>>> neginf = float('-inf')
>>> neginf, -1E400
(-inf, -inf)
>>> nan = float('nan')
>>> nan, inf * 0.
(nan, nan)

It would seem that in Python there is no built-in support for Inf, NaN, and -Inf, and the above example is accurate! But, it is useless verbose:

$ python2.7
>>> 1e400
inf
>>> 1e400 * 0
nan
>>> -1e400 * 0
nan
>>> -1e400
-inf
$ python3
>>> 1e400
inf
>>> 1e400 * 0
nan
>>> -1e400 * 0
nan
>>> -1e400
-inf

1 * 10 ^ 400. inf nan , , inf nan ?

, PEP , .

Answer 1

, .

, :

import math

print(math.inf)
print(-math.inf)
print(math.nan)

:

inf
-inf
nan

Answer 2

( "")

np.nan