On 18 Nov 2005 05:08:39 -0800, "[EMAIL PROTECTED]" <[EMAIL PROTECTED]> wrote:
>This works exactly as you would expect::
>
> from time import sleep
> def foo(on='ABC'):
> for e in list(on):
> sleep(1)
> yield e
>
>When I run this on the command line It takes about 3 seconds to
>complete and the first letter is shown after 1 second.
>But, how do I wrap the function somewhere else::
>
> from time import sleep
> def foo(on):
> for e in list(on):
> sleep(1)
> yield e
>
> def wrapper(x):
> if x < 0:
> return foo('ABC')
> else:
> return foo('XYZ')
>
>When I run this, variable three letters are shown and it takes 3
>seconds for the whole thing to complete. The problem is that the whole
>iteration is glogged up in the wrapper() function because the first
>letter is shown after 3 seconds and then all letters are shown at the
>same time.
>
>How do I wrap functions that return iterators? ...if possible.
>
Make the wrapper itself an iterable? E.g., is this the effect you wanted?
>>> from time import sleep
>>> def foo(on):
... for e in on:
... sleep(1)
... yield e
...
>>> def wrapper(x):
... if x < 0:
... for e in foo('ABC'): yield e
... else:
... for e in foo('XYZ'): yield e
...
>>> wrapper(-1)
<generator object at 0x02EF3D8C>
>>> import sys
>>> for c in wrapper(-1): sys.stdout.write(c); sys.stdout.flush()
...
ABC>>>
>>> for c in wrapper(+1): sys.stdout.write(c); sys.stdout.flush()
...
XYZ>>>
Regards,
Bengt Richter
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