Python Loop Double Printing

Question

Using the code below, I am able to get the correct answer, however it is repeated twice.

For instance, I would only want a result of [1.2038, 1.206], but the code below prints [1.2038, 1.206, 1.2038, 1.206]. Anybody knows what is wrong with my code? Any help would be greatly appreciated. Thanks!

spot = [1.2020, 1.2040]
forwardSwap = [0.0018, 0.0020]
forwardOutright = []

for i in range(len(spot)):
    for i in range(len(forwardSwap)):
        forwardOutright.append(spot[i] + forwardSwap[i])

print forwardOutright

Answer 1

You should zip instead of a nested loop to iterate both lists concurrently:

forwardOutright = [x+y for x, y in zip(spot, forwardSwap)]

Answer 2

As per the given code in your question, both of your loops are using a variable named as i.

for i in range(len(spot)):
    for i in range(len(forwardSwap)):