Home Original page

List of given type

Mike C. Fletcher mcfletch at rogers.com
Mon Mar 31 20:55:47 EST 2003 
Creating type-restricted lists is useful when creating self-assembling 
or largely automatically-assembled software.  The system can catch 
attempts to assign objects of the wrong type, reason about how to coerce 
an assigned value to the right type, etceteras.  Similarly, the GUI 
system can use introspection to present constructors to create 
appropriate values for the list/collection.

For pointers on how to declare something like this:

http://cvs.sourceforge.net/cgi-bin/viewcvs.cgi/wxpypropdist/properties/basictypes/rlist.py?rev=HEAD&content-type=text/vnd.viewcvs-markup

is a base-class which allows you to call a method on each addition to a 
list, where you can then do the type-checking necessary to support 
type-restriction. While:

http://cvs.sourceforge.net/cgi-bin/viewcvs.cgi/wxpypropdist/properties/basictypes/list_types.py?rev=HEAD&content-type=text/vnd.viewcvs-markup

is the actual implementation of "list-of-X" for the 
basictypes/basicproperty packages.

However, I'm guessing that the original poster may have been doing some 
premature optimisation, thinking that they needed such things when 
really the restrictions aren't necessary.  Unless you're dealing with 
automatically assembling software, the type-specifications aren't really 
that useful for Python code.

Enjoy,
Mike

John Machin wrote:

>Zaur Shibzoukhov <szport at fromru.com> wrote in message news:<mailman.1049055286.13086.python-list at python.org>...
>
>  
>
>>I need standard list of objects with a given type:
>>list of int, list of float, list of list, list of dict, list of string, ... - list of any type.
>>
>>    
>>
>
>A silly question: WHY???
>  
>
_______________________________________
  Mike C. Fletcher
  Designer, VR Plumber, Coder
  http://members.rogers.com/mcfletch/
More information about the Python-list mailing list