"Andrew Koenig" <[EMAIL PROTECTED]> writes:
> 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.
Normally you'd define a class and give it __iter__ and next operations.
I guess that can get messy. Does it qualify as easy for your purposes?
> 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.
You can make an internal function that's a generator with a yield
statement (or a generator expression instead of a function, if simple
enough). The class's 'next' method would loop through the generator
and return each value from it.
Let me try your example:
class kviter:
def __init__(self, d):
self.d = d
def __iter__(self):
def iter1(d, s=self):
for k in d:
# lambda not really needed here, but you wanted value to
# be callable instead of just an attribute
s.value = (lambda r=d[k]: r)
yield k
return iter1(self.d)
a = {1:5,2:6,3:7}
it = kviter(a)
for b in it:
print b, it.value()
>>> ## working on region in file /usr/tmp/python-15915wBw...
1 5
2 6
3 7
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