recursion

[Ian Clark]

Neil Cerutti wrote:
> On 2007-09-13, Gigs_ <gigs at hi.t-com.hr> wrote:
>> Can someone explain me this
>>
>>>>> def f(l):
>> 	if l == []:
>> 		return []
>> 	else:
>> 		return f(l[1:]) + l[:1]  # <= cant figure this, how is all sum at the end?
> 
> In plain English, the above program says:
> 
> The sum of the items in list l is zero if the list is empty.
> Otherwise, the sum is the value of the first item plus the sum of
> the rest of the items in the list.

Am I missing something? What does this have to do with summing?

     >>> def f(l):
     ...     if l == []:
     ...         return []
     ...     else:
     ...         return f(l[1:]) + l[:1]
     ...
     >>> f([1, 2, 3, 4])
     [4, 3, 2, 1]

Ian