On Thu, Dec 22, 2011 at 4:45 PM, GZ <zyzhu2...@gmail.com> wrote:
> def h():
> if condition=true:
> #I would like to return an itereator with zero length
> else:
> for ...: yield x
Easy. Just 'return' in the conditional.
>>> def h():
if condition:
return
for i in range(4): yield i
>>> condition=False
>>> h()
<generator object h at 0x01913E68>
>>> for i in h(): print(i)
0
1
2
3
>>> condition=True
>>> h()
<generator object h at 0x01079E40>
>>> for i in h(): print(i)
>>>
A generator object is returned since the function contains a 'yield'.
On one of the branches, nothing will ever be yielded and StopIteration
will be raised immediately.
You could probably also raise StopIteration directly, but it's not necessary.
ChrisA
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