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
