Question

I have the following function:

>>> def rule(x):
...     rule = bin(x)[2:].zfill(8)
...     rule = str(rule)
...     print rule

I am trying to convert rule into a string, but when I run the following command, here is what I get:

>>> type(rule(20))
00010100
<type 'NoneType'>

What is a NoneType variable and how can I convert this variable into a string?

Thanks,

Answer 1

you need to do:

def rule(x):
    return bin(x)[2:].zfill(8)

All functions return None implicitly if no return statement was encountered during execution of the function (as it is in your case).