In [8]:

    

def fibonacci(n):
    """return Nth number in the Fibonacci series"""
    a, b = 0, 1
    while n:
        a, b = b, a + b
        n -= 1
    return a


    

In [10]:

    

for n in range(20):
    print(fibonacci(n))


    

    




0
1
1
2
3
5
8
13
21
34
55
89
144
233
377
610
987
1597
2584
4181

In [13]:

    

for i, n in enumerate(range(20)):
    print('%2d -> %4d' % (i, fibonacci(n)))


    

    




 0 ->    0
 1 ->    1
 2 ->    1
 3 ->    2
 4 ->    3
 5 ->    5
 6 ->    8
 7 ->   13
 8 ->   21
 9 ->   34
10 ->   55
11 ->   89
12 ->  144
13 ->  233
14 ->  377
15 ->  610
16 ->  987
17 -> 1597
18 -> 2584
19 -> 4181

In [3]:

    

fibonacci


    

    
Out[3]:





<function __main__.fibonacci>

In [4]:

    

fibonacci.__doc__


    

    
Out[4]:





'return Nth number in the Fibonacci series'

In [5]:

    

help(fibonacci)


    

    




Help on function fibonacci in module __main__:

fibonacci(n)
    return Nth number in the Fibonacci series

In [6]:

    

fibonacci?