Get the nth Fibonacci number.

fibonacci.py

def f_simple_yet_stupid(n):
    if n == 1 or n == 2:
        return 1
    return f(n - 1) + f(n - 2)

def f(n):
    a = [0, 0, 1]
    for i in range(n - 1):
        a[:2] = a[1:]
        a[2] = a[0] + a[1]
    return a[2]

import time

s = time.time()
print f(100000)
print time.time() - s

This is also stupid. How about:

def fibonacci_generator():
    a, b = 0, 1
    while True:
        yield a
        a, b = b, a + b

s = time.time()
for i, f in enumerate(fibonacci_generator()):
    if i == 100000:
        print f
        break
print time.time() - s