[Python-Dev] Proposal: add odict to collections

Nick Coghlan ncoghlan at gmail.com
Sun Jun 15 10:14:12 CEST 2008

dbpokorny at gmail.com wrote:
> -1 for ordered dict
> +1 for sorted dict

Build the ordered dict, then sort it in-place afterwards, just like a 
list (alternatively, build a normal dict then feed sorted(orig.items()) 
to the ordered dict constructor).

The point of an ordered dict is that unlike a normal dict, the order the 
keys are returned is well defined at the interface level, rather than 
arbitrary and implementation-defined.

David Wolever's example of a normal dict() with an associated key list 
is an excellent way of thinking about the proposed semantics.

Having a fast ordered dict in the standard library also opens up the 
possibility of eventually using such a thing for keyword arguments at 
some point in the future. How nice would it be to be able to just write:

  t = namedtuple(a=1, b=2, c=3)

instead of:

   c = namedtuple("a b c")
   t = c(a=1, b=2, c=3)


Nick Coghlan   |   ncoghlan at gmail.com   |   Brisbane, Australia

More information about the Python-Dev mailing list