FrozenOrderedDict

About

FrozenOrderedDict is a immutable wrapper around an OrderedDict.

FrozenOrderedDict is similar to frozendict, and with regards to immutability it solves the same problems:

  • Because dictionaries are mutable, they are not hashable and cannot be used in sets or as dictionary keys.

  • Nasty bugs can and do occur when mutable data structures are passed around.

It can be initialized just like a dict or OrderedDict. Once instantiated, an instance of FrozenOrderedDict cannot be altered, since it does not implement the MutableMapping interface.

It does implement the Mapping interface, so can be used just like a normal dictionary in most cases.

In order to modify the contents of a FrozenOrderedDict, a new instance must be created. The easiest way to do that is by calling the .copy() method. It will return a new instance of FrozenOrderedDict initialized using the following steps:

  1. A copy of the wrapped OrderedDict instance will be created.

  2. If any arguments or keyword arguments are passed to the .copy() method, they will be used to create another OrderedDict instance, which will then be used to update the copy made in step #1.

  3. Finally, self.__class__() will be called, passing the copy as the only argument.

API Reference

class cawdrey.FrozenOrderedDict(*args, **kwds)[source]

An immutable OrderedDict. It can be used as a drop-in replacement for dictionaries where immutability is desired.

__abstractmethods__ = frozenset({})
__annotations__ = {'dict_cls': typing.Union[typing.Type, NoneType]}
__args__ = None
__contains__(key)
Return type

Any

__copy__(*args, **kwargs)
__eq__(other)

Return self==value.

__extra__ = None
__getitem__(key)
Return type

Any

__hash__()[source]

Return hash(self).

Return type

int

__init__(*args, **kwargs)[source]

Initialize self. See help(type(self)) for accurate signature.

__iter__()
__len__()
Return type

int

__module__ = 'cawdrey.frozenordereddict'
static __new__(cls, *args, **kwds)

Create and return a new object. See help(type) for accurate signature.

__next_in_mro__

alias of builtins.object

__orig_bases__ = (cawdrey.base.FrozenBase[~KT, ~VT],)
__origin__ = None
__parameters__ = (~KT, ~VT)
__repr__()

Return repr(self).

Return type

str

__reversed__ = None
__slots__ = ()
__subclasshook__()

Abstract classes can override this to customize issubclass().

This is invoked early on by abc.ABCMeta.__subclasscheck__(). It should return True, False or NotImplemented. If it returns NotImplemented, the normal algorithm is used. Otherwise, it overrides the normal algorithm (and the outcome is cached).

__tree_hash__ = -9223366107695456369
__weakref__

list of weak references to the object (if defined)

copy(*args, **kwargs)[source]

Return a copy of the FrozenOrderedDict.

Parameters

  • args –

  • kwargs –

Returns

Return type

dict_cls

alias of collections.OrderedDict

classmethod fromkeys(*args, **kwargs)

Returns a new dict with keys from iterable and values equal to value.

get(k[, d]) → D[k] if k in D, else d. d defaults to None.
items() → a set-like object providing a view on D’s items
keys() → a set-like object providing a view on D’s keys
values() → an object providing a view on D’s values