SHOCK: WHY None?

[Ben Finney]

n00m <n00m at narod.ru> writes:

> def f(i,sm):
>     if i+1==len(a):
>         print sm+a[i]
>         return sm+a[i]
>     else:
>         f(i+1,sm+a[i])
> 
> a=[1,2,3,4,5]
> 
> print f(0,0)
> 
> >>>
> 15
> None
> >>>

Here's one to meditate on:

    >>> def foo():
    ...     print "foo"
    ... 
    >>> print foo()
    foo
    None
    >>> def bar():
    ...     return "bar"
    ... 
    >>> print bar()
    bar
    >>> def baz():
    ...     pass
    ... 
    >>> print baz()
    None

It should be fairly clear how these three are different. If not, I
suspect you haven't worked your way through the Python tutorial;
please do so.

    <URL:http://www.python.org/tut/>

-- 
 \          "Are you pondering what I'm pondering?" "Well, I think so, |
  `\    Brain, but if Jimmy cracks corn, and no one cares, why does he |
_o__)                        keep doing it?"  -- _Pinky and The Brain_ |
Ben Finney