一個Python程序員的進化

    def factorial(x):
        if x == 0:
            return 1
        else:
            return x * factorial(x - 1) //遞歸！不簡單啊！
    print factorial(6)

    def factorial(x):
        result = 1
        i = 2
        while i <= x:
            resultresult = result * i
            ii = i + 1
        return result
    print factorial(6)

    def fact(x): #{
        result = i = 1;   //連續賦值！
        while (i <= x): #{
            result *= i;
            i += 1;
        #}
        return result;
    #}
    print(fact(6))

    @tailcall
    def fact(x, acc=1):
        if (x > 1): return (fact((x - 1), (acc * x)))  //遞歸！
        else:       return acc
    print(fact(6))

    def Factorial(x):
        res = 1
        for i in xrange(2, x + 1): //工具!
            res *= i
        return res
    print Factorial(6)

    def fact(x):
        return x > 1 and x * fact(x - 1) or 1 //語法!
    print fact(6)

   f = lambda x: x and x * f(x - 1) or 1 //匿名函數+語法!
    print f(6)

    fact = lambda x: reduce(int.__mul__, xrange(2, x + 1), 1) //匿名函數+工具+底層!
    print fact(6)

    import sys
    @tailcall
    def fact(x, acc=1):
        if x: return fact(x.__sub__(1), acc.__mul__(x)) //直接用底層！別人看不懂！
        return acc
    sys.stdout.write(str(fact(6)) + '\n')

    from c_math import fact //用標準庫！
    print fact(6)

   from c_maths import fact
    print fact(6)

    def factorial(x):
        #-------------------------------------------------
        #--- Code snippet from The Math Vault          ---
        #--- Calculate factorial (C) Arthur Smith 1999 ---
        #-------------------------------------------------
        result = str(1)
        i = 1 #Thanks Adam
        while i <= x:
            #result = result * i  #It's faster to use *=
            #result = str(result * result + i)
               #result = int(result *= i) #??????
            result = str(int(result) * i)  //不斷優化！
            #result = int(str(result) * i)
            i = i + 1
        return result
    print factorial(6)

    import os
    def fact(x):
        os.system('factorial ' + str(x)) //代碼量少！
    fact(6)
Windows 程序員
    NULL = None
    def CalculateAndPrintFactorialEx(dwNumber,
                                     hOutputDevice,
                                     lpLparam,
                                     lpWparam,
                                     lpsscSecurity,
                                     *dwReserved):
        if lpsscSecurity != NULL:
            return NULL #Not implemented
        dwResult = dwCounter = 1
        while dwCounter <= dwNumber:
            dwResult *= dwCounter
            dwCounter += 1
        hOutputDevice.write(str(dwResult))
        hOutputDevice.write('\n')
        return 1
    import sys
    CalculateAndPrintFactorialEx(6, sys.stdout, NULL, NULL, NULL, //自個都暈！
     NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL)

企業級程序員

    def new(cls, *args, **kwargs):
        return cls(*args, **kwargs)
    class Number(object):
        pass
    class IntegralNumber(int, Number):
        def toInt(self):
            return new (int, self)
    class InternalBase(object):
        def __init__(self, base):
            self.base = base.toInt()
        def getBase(self):
            return new (IntegralNumber, self.base)
    class MathematicsSystem(object):
        def __init__(self, ibase):
            Abstract
        @classmethod
        def getInstance(cls, ibase):
            try:
                cls.__instance
            except AttributeError:
                cls.__instance = new (cls, ibase)
            return cls.__instance
    class StandardMathematicsSystem(MathematicsSystem):
        def __init__(self, ibase):
            if ibase.getBase() != new (IntegralNumber, 2):
                raise NotImplementedError
            self.base = ibase.getBase()
        def calculateFactorial(self, target):
            result = new (IntegralNumber, 1)
            i = new (IntegralNumber, 2)
            while i <= target:
                result = result * i
                i = i + new (IntegralNumber, 1)
            return result
    print StandardMathematicsSystem.getInstance(new (InternalBase,
    new (IntegralNumber, 2))).calculateFactorial(new (IntegralNumber, 6))   //面向對象！