question about for cycle

[Duncan Booth]

"fdu.xiaojf at gmail.com" <fdu.xiaojf at gmail.com> wrote:

>>> Sometime it maybe a waste to generate all possible combinations of
>>> i,j first. 
>> 
>> It doesn't; read about generator expressions at
>> http://www.python.org/dev/peps/pep-0289/ 
>> 
>> George
>> 
> Thanks, I didn't realize that.
> 
> However, I still think labeled break and continue is a valuable
> feature, which is easier to understand and to use.
> 
Can you come up with a realistic example where you think a labelled break 
would be easier to understand and use? A concrete example would really help 
if you hope to persuade anyone that your way is better.

I find that Python's ability to extract the control part of a loop into a 
generator is an extremely powerful way to make loops much clearer for 
several reasons: you separate completely the 'what we are looping over', 
and 'when do we stop' from the 'what do we then do with each item'; also 
you have an opportunity to give the code controlling the loop a separate 
(and meaningful) name.