趣文：Python程序员的进化史

导读：下面代码来自 fmeyer ，列举了各种程序员所写的阶乘算法代码，甚至包括网页设计师的。

#新手程序员

[plain] view plain copy print?def factorial(x): if x == 0: return 1 else: return x * factorial(x - 1) print factorial(6)

def factorial(x):
if x == 0:
return 1
else:
return x * factorial(x - 1)
print factorial(6)

#有一年 Pascal 经验的程序员

[plain] view plain copy print?def factorial(x): result = 1 i = 2 while i <= x: result = result * i i = i + 1 return result print factorial(6)

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

#有一年 C 经验的程序员

[cpp] view plain copy print?def fact(x): #{
result = i = 1;
while (i <= x): #{
result *= i;
i += 1;
#}
return result;
#}
print(fact(6))

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

#}
print(fact(6))

#有一年 SICP 经验的程序员

[plain] view plain copy print?@tailcall def fact(x, acc=1): if (x > 1): return (fact((x - 1), (acc * x))) else: return acc print(fact(6))

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

#有一年 Python 经验的程序员

[python] view plain copy print?def Factorial(x): res = 1 for i in xrange(2, x + 1): res *= i return res print Factorial(6)

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

[python] view plain copy print?def fact(x): return x > 1 and x * fact(x - 1) or 1 print fact(6)

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

#更懒惰的Python程序员

[python] view plain copy print?f = lambda x: x and x * f(x - 1) or 1 print f(6)

f = lambda x: x and x * f(x - 1) or 1
print f(6)

#专家级Python程序员

[python] view plain copy print?import operator as op import functional as f fact = lambda x: f.foldl(op.mul, 1, xrange(2, x + 1)) print fact(6)

import operator as op
import functional as f
fact = lambda x: f.foldl(op.mul, 1, xrange(2, x + 1))
print fact(6)

#Python 黑客

[python] view plain copy print?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’)

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')

#专家级程序员

[plain] view plain copy print?import c_math fact = c_math.fact print fact(6)

import c_math
fact = c_math.fact
print fact(6)

#英国专家级程序员 （译注：在英式英语中，“数学”的简写，多用“maths”，不是“math”。）

[plain] view plain copy print?import c_maths fact = c_maths.fact print fact(6)

import c_maths
fact = c_maths.fact
print fact(6)

#网页设计师

[plain] view plain copy print?def factorial(x):
#————————————————-
#— 这段代码是从 Math Vault 那弄过来滴—
#— 计算阶乘 （C）亚瑟·史密斯 1999年—
#————————————————-
result = str(1)
i = 1 #谢谢亚当
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)

def factorial(x):
#-------------------------------------------------
#--- 这段代码是从 Math Vault 那弄过来滴---
#--- 计算阶乘 （C）亚瑟·史密斯 1999年---
#-------------------------------------------------
result = str(1)
i = 1 #谢谢亚当
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

[plain] view plain copy print?import os
def fact(x):
os.system(‘factorial ’ + str(x))
fact(6)

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

#Windows 程序员

[plain] view plain copy print?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, NULL, NULL, NULL, NULL, NULL)

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, NULL, NULL, NULL, NULL, NULL)

#企业程序员

[plain] view plain copy print?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))

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))

下面代码是kohashi给出的，他说是在邮局看到的。

[plain] view plain copy print?#VBA 程序员 def factorial(x): if x == 0: return 1 if x == 1: return x if x == 2: return x * (x-1) if x == 3: return x * (x-1) * (x-2) if x == 4: return x * (x-1) * (x-2) * (x-3) if x == 5: return x * (x-1) * (x-2) * (x-3) * (x-4) if x == 6: return x * (x-1) * (x-2) * (x-3) * (x-4) * (x-5) print factorial(6)

#VBA 程序员
def factorial(x):
if x == 0:
return 1
if x == 1:
return x
if x == 2:
return x * (x-1)
if x == 3:
return x * (x-1) * (x-2)
if x == 4:
return x * (x-1) * (x-2) * (x-3)
if x == 5:
return x * (x-1) * (x-2) * (x-3) * (x-4)
if x == 6:
return x * (x-1) * (x-2) * (x-3) * (x-4) * (x-5)
print factorial(6)

原文：fmeyer 编译：伯乐在线 – 黄利民