Probably somewhat silly newbie question

[James Stroud]

James Stroud wrote:
> elgrandchignon at gmail.com wrote:
> 
>> Hi all--
>>
>> Trying to learn Python w/little more than hobbyist (bordering on pro/
>> am, I guess) Perl as a background.
>>
>> My problem is, I have a list of departments, in this instance, things
>> like "Cheese", "Bakery", et al. (I work @ a co-op health food store).
>> I've populated a list, 'depts', w/these, so that their indexes match
>> our internal indexing (which skips a few #'s).
>>
>> Now, I'd like to simply generate-- and be able to refer to-- a bunch
>> of other lists-sets (for subdepartments) by iterating through this
>> list, and naming each of these subdepartment lists "categoryx", where
>> x is the index # from the master 'depts' list.  And then be able to
>> populate & refer to these lists by accessing their variable-including
>> name.
>>
>> In Perl, it's a fairly trivial matter to use a string variable in
>> naming some other kind of variable-- not sure about Python though.  My
>> initial, very weak stab at it (don't laugh!) went something like this:
>>
>> for i in range(len(depts)):
>>     if depts[i]:
>>         categorylistdeptname = 'category' + str(i)
>>         categorylistdeptname = []
>>
>> Not sure what that wound up doing, but it sure didn't seem to work.
> 
> 
> First, your are rebinding categorylistdeptname in the loop every time.
> 
> But you probably want a dict (in python 2.4 or later):
> 
> 
>    deptdict = dict((dept, []) for dept in depts))
> 
> And this gets what you want, believe it or not.
> 
> Now you can populate each list:
> 
>    deptdict['Bakery'].append("Donuts")
>    deptdict['Bulk'].extend(["Granola", "Rasins"])
> 
> And work witht the lists by name:
> 
>    for item in deptdict['Bulk']:
>      print item
>      # prints "Granola", "Rasins", etc.
> 
> 
> James
> 

Typo, too many parens. Should be:

      deptdict = dict((dept, []) for dept in depts)