Split a list into two parts based on a filter?

[Terry Reedy]

On 6/12/2013 12:57 PM, Fábio Santos wrote:
> Why is there no builtin to consume a generator? I find that odd.

There are several builtins than consume generators -- and do something 
useful with the yielded objects. What you mean is "Why is there no 
builtin to uselessly consume a generator?" The question almost answers 
itself. A generator generates objects to be used.

> On Wed, Jun 12, 2013 at 5:28 PM, Serhiy Storchaka <storchaka at gmail.com> wrote:

>> 12.06.13 09:32, Phil Connell написав(ла):
>>> You could equivalently pass the generator to deque() with maxlen=0 -
>>> this consumes the iterator with constant memory usage.

>> any((new_songs if s.is_new() else old_songs).append(s) for s in songs)

The problem here is that the generator generates and yields an unwanted 
sequence of None (references) from the append operations. The proper 
loop statement

for s in songs:
     (new_songs if s.is_new() else old_songs).append(s)

simply ignores the None return of the appends. Since it does not yield 
None over and over, no extra code is needed to ignore what should be 
ignored in the first place.

-- 
Terry Jan Reedy