evenfibonacci.py

"""
https://projecteuler.net/problem=2
Even Fibonacci numbers
Each new term in the Fibonacci sequence is generated by adding the previous two terms. By starting with 1 and 2, the first 10 terms will be:
1, 2, 3, 5, 8, 13, 21, 34, 55, 89, ...
By considering the terms in the Fibonacci sequence whose values do not exceed four million, find the sum of the even-valued terms.
"""

def fibonacci(limit):
    a, b, even = 1, 2, []
    while b < limit:
        if b%2 == 0: even.append(b)
        c = a + b
        a = b
        b = c
    return sum(even)

print(fibonacci(4000000))