[Python-Dev] LinkedHashSet/LinkedHashMap equivalents (original) (raw)

"Martin v. Löwis" martin at v.loewis.de
Thu Mar 10 00:45:08 CET 2005

John Williams wrote:

The other use case I have is for dealing with data where the iteration order doesn't matter to the program but it does matter to users. For instance, consider the ConfigParser's write method. Any ordering of values in the output is functionally equivalent, but the original data is likely to have come from a file that was arranged in some meaningful order, and it would be nice to preserve that order, especially if it can be done with no extra effort.

That is a good example, IMO. But then, in the specific case, the dictionary for each section is created deeply inside ConfigParser, with the lines

                     cursect = {'__name__': sectname}
                     self._sections[sectname] = cursect

So this uses a builtin dict, and there is no easy way to override it for the application.

Of course, given your reasoning, ConfigParser should use an OrderedDictionary (probably both for cursect and for self._sections), in which case this would all be transparent to the application.

Regards, Martin

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