Assigning to lists with arbitrary names

Christian Tanzer tanzer at swing.co.at
Thu Oct 11 08:57:02 CEST 2001


Cliff Wells <logiplexsoftware at earthlink.net> wrote:

> On Wednesday 10 October 2001 09:55, Daniel Dittmar wrote:
> > > Here's the problem: I want to name each list list00 to list99. I don't
> > > want to do list[0] to list[99] (since each list is actually a list of
> > > lists, and I'd like to avoid a list of lists of lists  :).
> >
> > You could use a dictionary with keys 'list00' to 'list99', but I don't
> > think having a dictionary of lists of lists is that much better. Why not
> > subclass UserList for each kind of list? Then you could at least
> > distinguish between the different levels.
> 
> If you really _must_ have multiple variable names (IMHO a bad idea, since 
> later you will have to reference all those lists and hence hardwire those 
> names into your code which will make extensiblity murder - I still feel the 
> dictionary method I recommended earlier is a simpler and more extensible 
> solution) you could use something like:
> 
> 
> filenames = ["text01.txt", "text02.txt", ....]  # use fnmatch or glob to get  
>                                                         # the filenames in    
>                                                         # real life
> i = 0
> for filename in filenames:
>     listname = "list%02d" % i
>     exec("%s = MyImporter('%s')" % (listname, filename))
>     i += 1
> 
> Which will give you 100 lists with the names list00, list99, etc and a ton of 
> maintenence problems.

And it still uses a dictionary (just slightly hidden from your view)
so what's the point of such a gross hack?

I think the OP should consider getting rid of his fear of nested data
structures -- in Python they are your friend.

-- 
Christian Tanzer                                         tanzer at swing.co.at
Glasauergasse 32                                       Tel: +43 1 876 62 36
A-1130 Vienna, Austria                                 Fax: +43 1 877 66 92





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