Another (perhaps similar) import question

Gary Herron gherron at
Sat Jun 14 03:25:05 CEST 2008

Dan Yamins wrote:
>         What is the principle behind this? And, is there some simple
>         way (other than restarting the interpreter) of "reloading"
>         that wipes out the old attributes associated with a given name
>         so that spurious attributes do not remain?
>     No.
>     Conclusion:  Don't use reload (ever).  A dozen years of Python
>     programming, and I've never used it even once.   If there is a
>     good use case for reload, you are probably years from being there.
> Gary, thanks very much for your help.    I suspected it was something 
> like this.  I still can quite tell however if the problem you describe 
> here is the same type of issue that was behind my first problem 
> (posted just before)  with the package imports. 
> I guess the think is,  feel that I basically _have_ to have some way 
> to reload.   I'm trying to code an application that allows users to 
> load new "mathematical operations" into a list of operations, and then 
> be able to update them after trying them out on some data variables 
> loaded into memory.   If every time they change the functions in the 
> modules to get them to produce the right results, they have to restart 
> the interpreter, they'll always lose the data variables that they've 
> loaded and operated on.    I need to find some way that they can 
> reload to access the modified version without having to re-do all the 
> command-line things they've done so far.   The reload command seems 
> like the only (and natural) way to do this.
> Thanks,
> Dan

Please keep responses to python-list discussion on python-list,  not my 
personal mail box. -- Thanks.

I'd suggest using modules for your system's code, and exec (or execfile) 
to read and parse user supplied code snippets.   The result of an exec 
of user supplied code will be very similar to a module import, and it 
will be using import and exec as they were intended.

Gary Herron

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