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Obfuscated factorial

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  Obfuscated factorial Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-10-26 11:55 +0000
    Re: Obfuscated factorial Vito De Tullio <vito.detullio@gmail.com> - 2013-10-26 14:50 +0200
    Re: Obfuscated factorial Chris Angelico <rosuav@gmail.com> - 2013-10-27 00:26 +1100
    Re: Obfuscated factorial Joshua Landau <joshua@landau.ws> - 2013-10-26 16:32 +0100
    Re: Obfuscated factorial Tim Chase <python.list@tim.thechases.com> - 2013-10-26 10:35 -0500
    Re: Obfuscated factorial Gene Heskett <gheskett@wdtv.com> - 2013-10-26 10:13 -0400
    Re: Obfuscated factorial Vito De Tullio <vito.detullio@gmail.com> - 2013-10-27 08:28 +0100

#57598 — Obfuscated factorial

Just for fun:


class Numberator:
    def __init__(self, number):
        self.__number = number
    def evaluate(self):
        return self.__number

class Multiplier:
    def __init__(self, multiplier, multiplicand):
        self.multiplier = multiplier
        self.multiplicand = multiplicand
    def evaluate(self):
        return self.multiplier * self.multiplicand.evaluate()

class FactorialBuilder:
    def __init__(self, number):
        if not isinstance(number, int):
            raise TypeError
        if number < 0:
            raise ValueError
        self.__number = number
    def build(self):
        multiplicand = Numberator(1)
        for n in range(2, self.__number + 1):
            multiplicand = Multiplier(n, multiplicand)
        return Factorialiser(multiplicand)

class Factorialiser:
    def __init__(self, evaluatorix):
        self.__evaluatorix = evaluatorix
    def calculate(self):
        return self.__evaluatorix.evaluate()

for i in range(16):
    print(i, FactorialBuilder(i).build().calculate())



And the output is:

0 1
1 1
2 2
3 6
4 24
5 120
6 720
7 5040
8 40320
9 362880
10 3628800
11 39916800
12 479001600
13 6227020800
14 87178291200
15 1307674368000



It goes without saying that this isn't Pythonic :-)


-- 
Steven

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#57601

Steven D'Aprano wrote:

> Just for fun:

[...]

you miss a FactoryFactory and a couple of *Manager.

Oh, and it should be xml-config-driven.


-- 
By ZeD

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#57604

On Sat, Oct 26, 2013 at 11:50 PM, Vito De Tullio
<vito.detullio@gmail.com> wrote:
> you miss a FactoryFactory and a couple of *Manager.
>
> Oh, and it should be xml-config-driven.

Or a metaclass and a few decorators. They're inherently Pythonic, right?

ChrisA

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#57620

On 26 October 2013 12:55, Steven D'Aprano
<steve+comp.lang.python@pearwood.info> wrote:
> Just for fun:
...
> for i in range(16):
>     print(i, FactorialBuilder(i).build().calculate())

Python already supports the factorial operator, -ⵘ. You just have to import it.

# Import statement
ⵘ = type("",(),{"__rsub__":lambda s,n:(lambda f,n:f(f,n))(lambda
f,z:round((2.5066282746310002*(z+0j+7.5)**(z+0.5)*2.718281828459045**(-z-7.5)*(0.99999999999980993+676.5203681218851/(z+1)-1259.1392167224028/(z+2)+771.32342877765313/(z+3)-176.61502916214059/(z+4)+12.507343278686905/(z+5)-0.13857109526572012/(z+6)+9.9843695780195716e-6/(z+7)+1.5056327351493116e-7/(z+8))).real)if
z>=0.5 else 3.141592653589793/(__import__("math").sin(3.141592653589793*z)*f(f,1-z)),n)})()

assert 2-ⵘ == 2

assert 3-ⵘ == 6

assert 4-ⵘ == 24

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#57621

On 2013-10-27 00:26, Chris Angelico wrote:
> On Sat, Oct 26, 2013 at 11:50 PM, Vito De Tullio
> <vito.detullio@gmail.com> wrote:
> > you miss a FactoryFactory and a couple of *Manager.
> >
> > Oh, and it should be xml-config-driven.
> 
> Or a metaclass and a few decorators. They're inherently Pythonic,
> right?

You are deploying it to The Cloud™ right?  And where is the
horizontal scalability?  Why doesn't it use NoSQL?

Bah, just goes to show that Python is no good for Enterprise™
applications ;-)

-tkc

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#57650

On Saturday 26 October 2013 10:12:33 Steven D'Aprano did opine:

> Just for fun:
> 
> 
> class Numberator:
>     def __init__(self, number):
>         self.__number = number
>     def evaluate(self):
>         return self.__number
> 
> class Multiplier:
>     def __init__(self, multiplier, multiplicand):
>         self.multiplier = multiplier
>         self.multiplicand = multiplicand
>     def evaluate(self):
>         return self.multiplier * self.multiplicand.evaluate()
> 
> class FactorialBuilder:
>     def __init__(self, number):
>         if not isinstance(number, int):
>             raise TypeError
>         if number < 0:
>             raise ValueError
>         self.__number = number
>     def build(self):
>         multiplicand = Numberator(1)
>         for n in range(2, self.__number + 1):
>             multiplicand = Multiplier(n, multiplicand)
>         return Factorialiser(multiplicand)
> 
> class Factorialiser:
>     def __init__(self, evaluatorix):
>         self.__evaluatorix = evaluatorix
>     def calculate(self):
>         return self.__evaluatorix.evaluate()
> 
> for i in range(16):
>     print(i, FactorialBuilder(i).build().calculate())
> 
> 
> 
> And the output is:
> 
> 0 1
> 1 1
> 2 2
> 3 6
> 4 24
> 5 120
> 6 720
> 7 5040
> 8 40320
> 9 362880
> 10 3628800
> 11 39916800
> 12 479001600
> 13 6227020800
> 14 87178291200
> 15 1307674368000
> 
Nice, but will it go to 70? :) 
> 
> It goes without saying that this isn't Pythonic :-)


Cheers, Gene
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)

"Out of register space (ugh)"
		-- vi
A pen in the hand of this president is far more
dangerous than 200 million guns in the hands of
         law-abiding citizens.

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#57726

Joshua Landau wrote:

> Python already supports the factorial operator, -ⵘ.

why use ⵘ (TIFINAGH LETTER AYER YAGH) when you can have the BANG? 방 (HANGUL 
SYLLABLE BANG)


> You just have to
> import it.
> 
> # Import statement
> ⵘ = type("",(),{"__rsub__":lambda s,n:(lambda f,n:f(f,n))(lambda
> f,z:round((2.5066282746310002*(z+0j+7.5)**(z+0.5)*2.718281828459045**(-
z-7.5)*(0.99999999999980993+676.5203681218851/(z+1)-1259.1392167224028/(z+2)+771.32342877765313/(z+3)-176.61502916214059/(z+4)+12.507343278686905/(z+5)-0.13857109526572012/(z+6)+9.9843695780195716e-6/(z+7)+1.5056327351493116e-7/(z+8))).real)if
> z>=0.5 else
> 3.141592653589793/(__import__("math").sin(3.141592653589793*z)*f(f,1-
z)),n)})()

I'm really, really impressed!

-- 
By ZeD

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