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infinity
========
|Build Status| |Version Status| |Downloads|
All-in-one infinity value for Python. Can be compared to any object.
Why?
----
* Python has ``float('inf')`` and ``float('-inf')``. However these simply
represent floating point infinity values. I wanted to create a class which can
be compared to any comparable object.
* Writing ``float('inf')`` is clumsy compared to just ``inf``
* ``pow(1, float('inf'))`` returns 1 whereas `it should be undefined`_. In
infinity this operation returns ``TypeError``.
* `When would you use Infinity`_?
.. _it should be undefined:
http://math.stackexchange.com/questions/319764
/1-to-the-power-of-infinity-why-is-it-indeterminate
.. _When would you use Infinity:
http://stackoverflow.com/questions/382603/when-would-you-use-infinity
Installation
------------
Simply grab the package from pypi::
pip install infinity
Supported python versions:
* Python 2.6
* Python 2.7
* Python 3.3
* Python 3.4
* Python 3.5
* PyPy
Object comparison
-----------------
The ``Infinity`` class supports rich comparison methods:
.. code-block:: python
>>> import sys
>>> from datetime import datetime
>>> from infinity import inf
>>> 3 < inf
True
>>> datetime(2000, 2, 2) < inf
True
>>> -inf < inf
True
>>> inf == inf
True
>>> -inf == -inf
True
Arithmetic operators
--------------------
It also supports arithmetic operators:
.. code-block:: python
>>> inf + inf
inf
>>> -inf - inf
-inf
>>> inf + 3
inf
>>> inf + datetime(2000, 2, 2)
inf
>>> 5 / inf
0
>>> 3 / -inf
0
>>> pow(inf, 0.5)
inf
The following operations raise ``TypeError`` exceptions:
.. code-block:: python
>>> inf - inf
Traceback (most recent call last):
...
TypeError: unsupported operand type(s) for -: 'Infinity' and 'Infinity'
>>> -inf + inf
Traceback (most recent call last):
...
TypeError: unsupported operand type(s) for +: 'Infinity' and 'Infinity'
>>> inf / inf # doctest: +IGNORE_EXCEPTION_DETAIL
Traceback (most recent call last):
...
TypeError: unsupported operand type(s) for /: 'Infinity' and 'Infinity'
>>> inf * 0
Traceback (most recent call last):
...
TypeError: unsupported operand type(s) for *: 'Infinity' and 'int'
>>> pow(inf, 0) # doctest: +IGNORE_EXCEPTION_DETAIL
Traceback (most recent call last):
...
TypeError: unsupported operand type(s) for ** or pow(): 'Infinity' and 'int'
>>> pow(1, inf) # doctest: +IGNORE_EXCEPTION_DETAIL
Traceback (most recent call last):
...
TypeError: unsupported operand type(s) for ** or pow(): 'int' and 'Infinity'
Type coercion
-------------
Infinity objects can be coerced to various types:
.. code-block:: python
>>> float(inf) == float('inf')
True
>>> float(-inf) == float('-inf')
True
>>> str(inf)
'inf'
>>> str(-inf)
'-inf'
>>> bool(inf)
True
>>> bool(-inf)
True
.. |Build Status| image:: https://travis-ci.org/kvesteri/infinity.png?branch=master
:target: https://travis-ci.org/kvesteri/infinity
.. |Version Status| image:: https://img.shields.io/pypi/v/infinity.svg
:target: https://pypi.python.org/pypi/infinity/
.. |Downloads| image:: https://img.shields.io/pypi/dm/infinity.svg
:target: https://pypi.python.org/pypi/infinity/
|
