Can anyone think of an easy technique for creating an object that acts like
a generator but has additional methods?
For example, it might be nice to be able to iterate through an associative
container without having to index it for each element. Right now, I can say
i = iter(d)
and then repeatedly calling i.next() gives us the keys for the elements.
But to get the corresponding value requires us to look up the key.
Of course one could define a generator that yields key-value pairs, along
the following lines:
def kviter(d):
for i in d:
yield i, d[i]
to hide the lookup. But this yields a tuple even when you don't want it.
In other words, I must now write
for k, v in kviter(d):
# whatever
and I can think of situations in which I don't really want both the key and
the value all the time.
So what I really want is something like this:
it = augiter(d)
for i in it:
if <some condition on i>:
foo(it.value())
In other words, I want "it" to support both the next and value methods (or
next and something else)
Of course I can write such a beast as a class, but that prevents me from
taking advantage of the yield statement in its implementation.
So my question is: Can you think of an easy way to write something that
looks like a generator (using yield), but can also incorporate methods other
than next?
--
http://mail.python.org/mailman/listinfo/python-list
