Factorials in Python

factorials.py

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


#Lazy Python programmer
def fact(x):
    return x > 1 and x * fact(x - 1) or 1
print fact(6)


#Lazier Python programmer
f = lambda x: x and x * f(x - 1) or 1
print f(6)


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


#Python hacker
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')

Wonderful