Yes, you can use del: del dct[key] Below is a demonstration: >>> from collections import OrderedDict >>> dct = OrderedDict() >>> dct[‘a’] = 1 >>> dct[‘b’] = 2 >>> dct[‘c’] = 3 >>> dct OrderedDict([(‘a’, 1), (‘b’, 2), (‘c’, 3)]) >>> del dct[‘b’] >>> dct OrderedDict([(‘a’, 1), (‘c’, 3)]) >>> In fact, you should always … Read more
Here’s a hack that almost gives you the syntax you want: class _OrderedDictMaker(object): def __getitem__(self, keys): if not isinstance(keys, tuple): keys = (keys,) assert all(isinstance(key, slice) for key in keys) return OrderedDict([(k.start, k.stop) for k in keys]) ordereddict = _OrderedDictMaker() from nastyhacks import ordereddict menu = ordereddict[ “about” : “about”, “login” : “login”, ‘signup’: “signup” … Read more
Your problem is that you are constructing a dict to give the initial data to the OrderedDict – this dict doesn’t store any order, so the order is lost before it gets to the OrderedDict. The solution is to build from an ordered data type – the easiest being a list of tuples: >>> from … Read more
In Python 3, dict.keys() and dict.values() return special iterable classes – respectively a collections.abc.KeysView and a collections.abc.ValuesView. The first one inherit it’s __eq__ method from set, the second uses the default object.__eq__ which tests on object identity.
You’ll have to create a new one since OrderedDict is sorted by insertion order. In your case the code would look like this: foo = OrderedDict(sorted(foo.items(), key=lambda x: x[1][‘depth’])) See http://docs.python.org/dev/library/collections.html#ordereddict-examples-and-recipes for more examples. Note for Python 2 you will need to use .iteritems() instead of .items().
Sorry, not possible. Dict literals and dict comprehensions map to the built-in dict type, in a way that’s hardcoded at the C level. That can’t be overridden. You can use this as an alternative, though: OrderedDict((i, i * i) for i in range(3)) Addendum: as of Python 3.6, all Python dictionaries are ordered. As of … Read more
You are doing it wrong. You need not only to insert values sequentially into dictionary, but also remove some elements and see how the order has changed after this. The next code demonstrates this: OrderedDictionary od = new OrderedDictionary(); Dictionary<String, String> d = new Dictionary<String, String>(); Random r = new Random(); for (int i = … Read more
Using next(reversed(od)) is a perfect way of accessing the most-recently added element. The class OrderedDict uses a doubly linked list for the dictionary items and implements __reversed__(), so this implementation gives you O(1) access to the desired element. Whether it is worthwhile to subclass OrderedDict() for this simple operation may be questioned, but there’s nothing … Read more
OrderedDict is a subclass of dict, and needs more memory to keep track of the order in which keys are added. This isn’t trivial. The implementation adds a second dict under the covers, and a doubly-linked list of all the keys (that’s the part that remembers the order), and a bunch of weakref proxies. It’s … Read more
Ever since Python 3.7, Python guarantees that keys in a dictionary will retain their insertion order. (They still don’t behave exactly the same as OrderedDict objects, though, as two dicts a and b can be considered equal a == b even if the order of the keys is different, whereas OrderedDict does check this upon … Read more