不久前，在互联网上出现了一篇有趣的文章，讲的是对于同一个问题，不同层次的Python程序员编出的Python代码，显示出了不同的风格，代码都很简单，有趣。下面让我们一起来看看一个Python程序猿进阶的全过程吧。(偷笑)

编程新手

def factorial(x):  
  if x == 0:  
    return 1  
  else:  
    return x * factorial(x - 1) //不简单啊，迭代，新手哦。 
print factorial(6)  

一年编程经验(学Pascal的)

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

一年编程经验(学C的)

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

一年编程经验(读过SICP)

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

一年编程经验(Python)

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

懒惰的Python程序员

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

更懒的Python程序员

f = lambda x: x and x * f(x - 1) or 1 //匿名函数，厉害。程序猿真是懒人做的！ 
print f(6)  

Python专家

fact = lambda x: reduce(int.__mul__, xrange(2, x + 1), 1)  
print fact(6)               //专家厉害啊。

 Python黑客

import sys  
@tailcall  
def fact(x, acc=1):  
  if x: return fact(x.__sub__(1), acc.__mul__(x))  
  return acc  
sys.stdout.write(str(fact(6)) + \'\\n\') //一般人压根看不懂。 

专家级程序员

from c_math import fact  
print fact(6)  

大英帝国程序员

from c_maths import fact  
print fact(6)  
Web设计人员
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)  
    #result = int(str(result) * i)  
    i = i + 1  
  return result  
print factorial(6) 

Unix 程序员

import os  
def fact(x):  
  os.system(\'factorial \' + str(x))  
fact(6)  

Windows 程序员

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,  
 NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL) //可能自己都晕菜了...

企业级程序员

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)) //面向对象，但就此题来说，又长又臭。