Could a more generic variant of this class work? In the same way that `sorted` can accept a comparison function, similar could be done for a dictionary-like class:
d = transformdict(key=str.lower) Strictly speaking, this would provide case-insensitive but not case-preserving behaviour. For any given use case, though, a function could instead be supplied to "normalise" the key (upper, lower, title case, etc) in a way that fits that case. I can't think of many real cases where multiple types of capitalisation would be useful within the same dictionary. Nigel On 10 September 2013 15:40, Richard Oudkerk <shibt...@gmail.com> wrote: > On 10/09/2013 3:15pm, Armin Rigo wrote: > >> Hi Richard, >> >> On Tue, Sep 10, 2013 at 3:42 PM, Richard Oudkerk <shibt...@gmail.com> >> wrote: >> >>> I guess another example is creating an "identity dict" (see >>> http://code.activestate.com/**lists/python-ideas/7161/<http://code.activestate.com/lists/python-ideas/7161/>) >>> by doing >>> >>> d = transformdict(id) >>> >> >> This is bogus, because only the id will be stored, and the original >> key object will be forgotten (and its id probably reused). >> > > Seems to work for me: > > >>> import collections > >>> d = collections.transformdict(id) > >>> L = [1,2,3] > >>> d[L] = None > >>> L in d > True > >>> [1,2,3] in d > False > >>> print(d[L]) > None > >>> d._data > {41444136: ([1, 2, 3], None)} > >>> list(d) > [[1, 2, 3]] > > However __repr__() is broken: > > >>> d > Traceback (most recent call last): > File "<stdin>", line 1, in <module> > File "C:\Repos\cpython-dirty\lib\**collections\abc.py", line 444, in > __repr__ > return '{0.__class__.__name__}({0._**mapping!r})'.format(self) > File "C:\Repos\cpython-dirty\lib\**collections\__init__.py", line 944, > in __repr__ > self._transform, repr(dict(self))) > TypeError: unhashable type: 'list' > > -- > Richard > > ______________________________**_________________ > Python-Dev mailing list > Python-Dev@python.org > https://mail.python.org/**mailman/listinfo/python-dev<https://mail.python.org/mailman/listinfo/python-dev> > Unsubscribe: https://mail.python.org/**mailman/options/python-dev/** > nigel%40nigelsmall.com<https://mail.python.org/mailman/options/python-dev/nigel%40nigelsmall.com> >
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