change of random state when pyc created??

[Dustan]

On May 6, 1:00 am, Steven D'Aprano
<s... at REMOVE.THIS.cybersource.com.au> wrote:
> On Sun, 06 May 2007 00:20:04 +0000, Alan Isaac wrote:
> >> Should you not expect to get the same result each time? Is that not
> >> the point of setting a constant seed each time you run the script?
>
> > Yes.  That is the problem.
> > If I delete module2.pyc,
> > I do not get the same result.
>
> I think you have missed what John Machin is pointing out. According to
> your original description, you get different results even if you DON'T
> delete module2.pyc.
>
> According to your original post, you get the _same_ behaviour the first
> time you run the script, regardless of the pyc file being deleted or not.
>
> You wrote:
>
> [quote]
> module1 sets a seed like this::
>
> if __name__ == "__main__":
>     random.seed(314)
>     main()
>
> I execute module1.py from the (Windows) shell.
> I get a result, let's call it result1.
> I execute it again. I get another result, say result2.
> Running it again and again, I get result2.
> [end quote]
>
> So, with module2.pyc file existing, you get result1 the first time you
> execute module1.py, and then you get result2 every time from then onwards.

Umm... no.

module2.pyc is created by the first run.

> How is that different from what you wrote next?
>
> [quote]
> Now I delete module2.pyc.
> I execute module1.py from the shell.
> I get result1.
> I execute it again; I get result2.
> From then on I get result2,
> unless I delete module.pyc again,
> in which case I once again get result1.
> [end quote]
>
> You get the same behaviour with or without module2.pyc: the first run of
> the script gives different results from subsequent runs. You can reset
> that first run by deleting module2.pyc.
>
> I'm still perplexed how this is possible, but now I'm more perplexed.
>
> If you want to send me the modules, I will have a look at them as well.
> Many eyes make for shallow bugs...
>
> --
> Steven.