Peter Pearson wrote: > On Mon, 03 May 2010 17:30:03 +0200, Peter Otten <__pete...@web.de> wrote: >> Victor Eijkhout wrote: >> >>> I have two long ints, both too long to convert to float, but their ratio >>> is something reasonable. How can I compute that? The obvious "(1.*x)/y" >>> does not work. >> >>>>> import fractions >>>>> x = 12345 * 10**1000 >>>>> y = 765 * 10**1000 >>>>> float(x) >> Traceback (most recent call last): >> File "<stdin>", line 1, in <module> >> OverflowError: long int too large to convert to float >>>>> fractions.Fraction(x, y) >> Fraction(823, 51) >>>>> float(_) >> 16.137254901960784 > > Does this still work if y = 765 * 10**1000 + 1 ? It looks > as if it might rely on x and y having a large common divisor.
You mean something like this? >>> import fractions >>> x = 765 * 10**1000 >>> fractions.gcd(x, x+1) 1L >>> float(fractions.Fraction(x, x+1)) 1.0 But my D'oh!* moment really was seeing Jerry Hill doing it with >>> from __future__ import division >>> x/(x+1) 1.0 Peter (*) I'm having a lot of these lately. Looks like I need a new brain. -- http://mail.python.org/mailman/listinfo/python-list
