variables exist

[Fredrik Lundh]

Scott David Daniels wrote:
> >... STeVe stressed that the try/except solution is only really
appropriate

> > for cases where the failure to have the variable defined is quite rare.
>
> Beware: C++ and Java have an immense overhead for exceptions.  Python
> has a very lightweight exception mechanism.  You should _very_seldom_
> choose exceptions or not on the basis of performance without measuring
> the actual use; you are sure to be surprised.
>
> Structure your code to be easiest to understand.  _If_ it is too slow,
> investigate ways to improve its performance.  The usual way is to
> build better data structures and use better algorithms.  Only in the
> core of a frequently used inner loop should you even care about the
> cost of exceptions.

you haven't really read this thread, have you?

</F>