Does Python have a function to reduce fractions?

LWZ picture LWZ · Jul 9, 2013 · Viewed 22.8k times · Source

For example, when I calculate 98/42 I want to get 7/3, not 2.3333333, is there a function for that using Python or Numpy?

Answer

John La Rooy picture John La Rooy · Jul 9, 2013

The fractions module can do that

>>> from fractions import Fraction
>>> Fraction(98, 42)
Fraction(7, 3)

There's a recipe over here for a numpy gcd. Which you could then use to divide your fraction

>>> def numpy_gcd(a, b):
...     a, b = np.broadcast_arrays(a, b)
...     a = a.copy()
...     b = b.copy()
...     pos = np.nonzero(b)[0]
...     while len(pos) > 0:
...         b2 = b[pos]
...         a[pos], b[pos] = b2, a[pos] % b2
...         pos = pos[b[pos]!=0]
...     return a
... 
>>> numpy_gcd(np.array([98]), np.array([42]))
array([14])
>>> 98/14, 42/14
(7, 3)