How on Factorial
arnodel at gmail.com
Wed Oct 27 10:27:21 CEST 2010
Chris Rebert <clp2 at rebertia.com> writes:
> On Tue, Oct 26, 2010 at 11:25 PM, Geobird <a1chandan at gmail.com> wrote:
>> I am a beginner in Python and would ask for a help.
>> I was searching for smaller version of code to calculate
>> factorial . Found this one
>> def fact(x):
>> return x > 1 and x * fact(x - 1) or 1
>> But I don't really get how ( ....x > 1 and x * fact(x - 1)....)
>> works .
> It exploits short-circuit evaluation
> (http://en.wikipedia.org/wiki/Short-circuit_evaluation ). This is
> stunt coding / code golf; no one should actually write factorial like
True. It's far too verbose. I'd go for something like:
f=lambda n:n<=0 or n*f(~-n)
I've saved a few precious keystrokes and used the very handy ~- idiom!
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