fibonacci sequence python
# WARNING: this program assumes the
# fibonacci sequence starts at 1
def fib(num):
"""return the number at index `num` in the fibonacci sequence"""
if num <= 2:
return 1
return fib(num - 1) + fib(num - 2)
# method 2: use `for` loop
def fib2(num):
a, b = 1, 1
for _ in range(num - 1):
a, b = b, a + b
return a
print(fib(6)) # 8
print(fib2(6)) # same result, but much faster