* Armin Ronacher wrote:
Some reasons why ordered dicts are a useful feature:
- in XML/HTML processing it's often desired to keep the attributes of an tag ordered during processing. So that input ordering is the same as the output ordering.
- Form data transmitted via HTTP is usually ordered by the position of the input/textarea/select field in the HTML document. That information is currently lost in most Python web applications / frameworks.
- Eaiser transition of code from Ruby/PHP which have sorted associative arrays / hashmaps.
- Having an ordered dict in the standard library would allow other libraries support them. For example a PHP serializer could return odicts rather then dicts which drops the ordering information. XML libraries such as etree could add support for it when creating elements or return attribute dicts.
I find this collection of cases pretty weak as an argument for implementing that in the stdlib. A lot of special purpose types would fit into such reasoning, but do you want to have all of them maintained here? nd -- Da fällt mir ein, wieso gibt es eigentlich in Unicode kein "i" mit einem Herzchen als Tüpfelchen? Das wär sooo süüss! -- Björn Höhrmann in darw