FrozenOrderedDict

About

FrozenOrderedDict is a immutable wrapper around an OrderedDict. It 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.

FrozenOrderedDict implements 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 FrozenOrderedDict(*args, **kwargs)

Bases: FrozenBase[~KT, ~VT]

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

Methods:

__contains__(key)	Return key in self.
__eq__(other)	Return self == other.
__getitem__(key)	Return self[key].
__iter__()	Iterates over the dictionary’s keys.
__len__()	Returns the number of keys in the dictionary.
__repr__()	Return a string representation of the DictWrapper.
copy(*args, **kwargs)	Return a copy of the FrozenOrderedDict.
fromkeys(iterable[, value])	Create a new dictionary with keys from iterable and values set to value.
get(k[, default])	Return the value for k if k is in the dictionary, else default.
items()	Returns a set-like object providing a view on the FrozenOrderedDict's items.
keys()	Returns a set-like object providing a view on the FrozenOrderedDict's keys.
values()	Returns an object providing a view on the FrozenOrderedDict's values.

__contains__(key)

Return key in self.

Parameters

key (object)

Return type

bool

__eq__(other)

Return self == other.

Return type

bool

__getitem__(key)

Return self[key].

Parameters

key (~KT)

Return type

~VT

__iter__()

Iterates over the dictionary’s keys.

Return type

Iterator[~KT]

__len__()

Returns the number of keys in the dictionary.

Return type

int

__repr__()

Return a string representation of the DictWrapper.

Return type

str

copy(*args, **kwargs)

Return a copy of the FrozenOrderedDict.

Parameters

• args

• kwargs

classmethod fromkeys(iterable, value=None)

Create a new dictionary with keys from iterable and values set to value.

Return type

FrozenBase[~KT, ~VT]

get(k, default=None)

Return the value for k if k is in the dictionary, else default.

Parameters

• k – The key to return the value for.

• default – The value to return if key is not in the dictionary. Default None.

Overloads

• get(k: ~KT) -> Optional[~VT]

• get(k: ~KT, default: Union[~VT, ~T] ) -> Union[~VT, ~T]

items()

Returns a set-like object providing a view on the FrozenOrderedDict's items.

Return type

AbstractSet[Tuple[~KT, ~VT]]

keys()

Returns a set-like object providing a view on the FrozenOrderedDict's keys.

Return type

AbstractSet[~KT]

values()

Returns an object providing a view on the FrozenOrderedDict's values.

Return type

ValuesView[~VT]

Copyright

Based on https://github.com/slezica/python-frozendict and https://github.com/mredolatti/python-frozendict .

Copyright (c) 2012 Santiago Lezica

Licensed under the MIT License:

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Also based on https://github.com/Marco-Sulla/python-frozendict

Copyright (c) Marco Sulla

Licensed under the GNU Lesser General Public License Version 3

Also based on https://github.com/wsmith323/frozenordereddict

Copyright (c) 2015 Warren Smith

Licensed under the MIT License:

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.