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711

answers:

3

Has anybody seen such a thing? Small self-sufficient modules are preferred.

+7  A: 

SymPy is a symbolic maths library written entirely in Python and has full support for rational numbers. From the tutorial:

>>> from sympy import *
>>> a = Rational(1,2)

>>> a
1/2

>>> a*2
1

>>> Rational(2)**50/Rational(10)**50
1/88817841970012523233890533447265625

There is also GMP for Python (GMPY) which, while not pure Python, is probably more efficient.

Robert Gamble
Thanks. SymPy's Rational is nice, if a little too intertwined with other parts of the library.
Constantin
+7  A: 

The fractions module from 2.6 can be ripped out if necessary. Grab fractions.py, numbers.py, and abc.py; all pure python modules.

Coady
True, i thought it would be much more difficult!
Constantin
+1  A: 

One more thing to try is Rat.py from demo folder in Python 2.5 maintenance branch. If i understand correctly, it is the daddy of 2.6 fractions. It's a single module without dependencies.

>>> from Rat import rat
>>> rat(1) / rat(3)
Rat(1,3)
>>> rat(1, 3) ** 2
Rat(1,9)

UPDATE: Nah, fractions.py is about 2.5 times faster for my task.

Constantin