This works:
def fact(x):
if x == 0 or x == 1:
return 1
else:
return reduce(operator.mul, xrange(1,x+1))
or
def factorial(n):
acc = 1
while n > 1:
acc = acc * n
n = n - 1
return acc
On 10/22/07, [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote:
>
> On Oct 22, 1:35 pm, Paul Rudin <[EMAIL PROTECTED]> wrote:
> > "[EMAIL PROTECTED]" <[EMAIL PROTECTED]> writes:
> > > On Oct 22, 7:50 am, Duncan Booth <[EMAIL PROTECTED]> wrote:
> > >> Py-Fun <[EMAIL PROTECTED]> wrote:
> > >> > I'm stuck trying to write a function that generates a factorial of
> a
> > >> > number using iteration and not recursion. Any simple ideas would
> be
> > >> > appreciated.
> >
> > >> This version avoids doing anything fancier than adding 1, so it
> should be
> > >> simple enough for anyone:
> >
> > >> def factorial(e):
> > >> a = 1
> > >> for b in range(e):
> > >> c = 0
> > >> for j in range(b, -1, -1):
> > >> for d in range(a):
> > >> c += 1
> > >> a = c
> > >> return a
> >
> > > Not simple enough for my taste:
> >
> > >>>> import gmpy
> > >>>> gmpy.fac(10)
> > > mpz(3628800)
> >
> > I haven't followed all this thread, but has anyone yet done:
> >
> > import operator
> > def fact(x):
> > return reduce(operator.mul, xrange(1,x))
>
> I hope not.
>
> >>> import operator
> >>> def fact(x):
> return reduce(operator.mul,xrange(1,x))
>
> >>> fact(3)
> 2
> >>> fact(2)
> 1
> >>> fact(1)
>
> Traceback (most recent call last):
> File "<pyshell#10>", line 1, in <module>
> fact(1)
> File "<pyshell#7>", line 2, in fact
> return reduce(operator.mul,xrange(1,x))
> TypeError: reduce() of empty sequence with no initial value
>
> >>> fact(0)
>
> Traceback (most recent call last):
> File "<pyshell#11>", line 1, in <module>
> fact(0)
> File "<pyshell#7>", line 2, in fact
> return reduce(operator.mul,xrange(1,x))
> TypeError: reduce() of empty sequence with no initial value
>
> I think you need to make it a bit more complicated.
>
> --
> http://mail.python.org/mailman/listinfo/python-list
>
--
Rafael Sachetto Oliveira
Sir - Simple Image Resizer
http://rsachetto.googlepages.com
--
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