Coding style

[Peter Otten]

Carl Banks wrote:

>     def process_values(lst):
>         if not lst:
>             return
>         do_expensive_initialization_step()
>         for item in lst:
>             do_something_with(item)
>         do_expensive_finalization_step()

> What if you called the function like this:
> 
>     process_values(x.strip() for x in values_lst)
> 
> Oops, now we've just gone through an expensive initialization and
> finalization for nothing (since values_lst was empty).  Maybe some
> subtle bugs introduced.  If we're lucky, the finalization step will
> throw an exception.

The good news is that the above has a 99 percent chance that it just works
with iterators/generators -- even though the writer may not have been aware
of them/they didn't exist when the code was written...

Peter