====== The Evolution of a Python Programmer  ======

A while back, clever snippets of code portraying how different people programming in Python went about solving the same problem, appeared on the internet. Needless to say, it was pretty funny and despite its popularity, not many people seem to know of it when I bring it up. Being as lazy as I am when it comes to these sorts of things, I am blogging about it now. Almost three years later. It has been posted and reposted dozens of times, but full of geek pride, I can proudly say that I helped create it by correcting some of the mistakes in the original. How’s that for major geek cred? 

===== Newbie Programmer =====

<code python>
def factorial(x):
    if x == 0:
        return 1
    else:
        return x * factorial(x - 1)
print factorial(6)
</code>

===== First Year Programmer (Studied Pascal) =====



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

===== First Year Programmer (Studied C) =====



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

===== First Year Programmer (Read SICP) =====



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

===== First Year Programmer (Python) =====



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

===== Lazy Python Programmer =====



<code python>
def fact(x):
    return x > 1 and x * fact(x - 1) or 1
print fact(6)
</code>

===== Lazier Python Programmer =====



<code python>
f = lambda x: x and x * f(x - 1) or 1
print f(6)
</code>

===== Python Expert Programmer =====


<code python>
fact = lambda x: reduce(int.__mul__, xrange(2, x + 1), 1)
print fact(6)
</code>

===== Python Hacker =====



<code python>
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')
</code>

===== EXPERT PROGRAMMER =====

<code python>
from c_math import fact
print fact(6)
</code>

===== BRITISH EXPERT PROGRAMMER =====

<code python>
from c_maths import fact
print fact(6)
</code>

===== Web Designer =====



<code python>
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)
</code>

===== Unix Programmer =====



<code python>
import os
def fact(x):
    os.system('factorial ' + str(x))
fact(6)
</code>

===== Windows Programmer =====

<code python>
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)
</code>

===== Enterprise Programmer =====

<code python>
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))
</code>

===== 参考  =====
  * http://metaleks.net/programming/the-evolution-of-a-python-programmer
  * http://dis.4chan.org/read/prog/1180084983/