frozndict

frozndict is a python package that acts as an alternative to frozenset, but for dictionaries.

🛠️ Requirements

frozndict requires Python 3.9 or above.

To install Python 3.9, I recommend using pyenv.

# install pyenv
git clone https://github.com/pyenv/pyenv ~/.pyenv

# setup pyenv (you should also put these three lines in .bashrc or similar)
# if you are using zsh
cat << EOF >> ~/.zshrc
# pyenv config
export PATH="${HOME}/.pyenv/bin:${PATH}"
export PYENV_ROOT="${HOME}/.pyenv"
eval "$(pyenv init -)"
EOF

# or if you using the default bash shell, do this instead:
cat << EOF >> ~/.bashrc
# pyenv config
export PATH="${HOME}/.pyenv/bin:${PATH}"
export PYENV_ROOT="${HOME}/.pyenv"
eval "$(pyenv init -)"
EOF
# Close and open a new shell session
# install Python 3.9.10
pyenv install 3.9.10

# make it available globally
pyenv global system 3.9.10

To manage the Python 3.9 virtualenv, I recommend using poetry.

# install poetry
curl -sSL https://install.python-poetry.org | python3 -
poetry --version
Poetry version 1.1.13

# Having the python executable in your PATH, you can use it:
poetry env use 3.9.10

# However, you are most likely to get the following issue:
Creating virtualenv frozndict-dxc671ba-py3.9 in ~/.cache/pypoetry/virtualenvs

ModuleNotFoundError

No module named 'virtualenv.seed.via_app_data'

at <frozen importlib._bootstrap>:973 in _find_and_load_unlocked

# To resolve it, you need to reinstall virtualenv through pip
sudo apt remove --purge python3-virtualenv virtualenv
python3 -m pip install -U virtualenv

# Now, you can just use the minor Python version in this case:
poetry env use 3.9.10
Using virtualenv: ~/.cache/pypoetry/virtualenvs/frozndict-dxc671ba-py3.9

🚨 Installation

With pip:

python3.9 -m pip install frozndict

With pipx:

python3.9 -m pip install --user pipx
pipx install --python python3.9 frozndict

🚸 Usage

>>> from frozndict import frozendict

# Empty immutable immutable dictionary.
>>> frozen_dict = frozendict({})
frozendict({})

# Non empty immutable immutable dictionary.
>>> frozen_dict = frozendict({"Greetings": "Hello World!"})
>>> frozen_dict
frozendict({'Greetings': 'Hello World!'})

# Get an item.
>>> frozen_dict["Greetings"]
'Hello World!'

# Copy a dictionary.
>>> frozen_dict_copy = frozen_dict.copy()
>>> frozen_dict_copy
{'Greetings': 'Hello World!'}

# Nested dictionary.
>>> frozen_dict_copy = frozendict({'x': 3, 'y': 4, 'z': {'a': 0, 'b': [3,1,{4,1},[5,9]]}}, c= 1)
>>> print(a.pretty_repr())
frozendict({
    x: 3,
    y: 4,
    z: {
        a: 0,
        b: [3, 1, {1, 4}, [5, 9]],
    },
    c: 1,
})

# Create an immutable dictionary using `fromkeys` method.
>>> frozen_dict = frozendict.fromkeys(["x", "y"], "5")
>>> frozen_dict
frozendict({'x': '5', 'y': '5'})

# Test uniqueness: frozendict(a=1,b=2) == frozendict(b=2,a=1)
>>> set([frozendict(a=1,b=2), frozendict(a=5), frozendict(b=2,a=1)])
{frozendict({'a': 5}), frozendict({'a': 1, 'b': 2})}

🚀 Similar Projects Comparaison

This project is similar to frozendict created by Marco Sulla.

>>> from frozndict import frozendict as myfrozendict
>>> from frozendict import frozendict

# create instances
>>> my_frozen_dict = myfrozendict({'x': 3, 'y': 4, 'z': {'a': 0, 'b': [3,1,{4,1},[5,9]]}}, c= 1)
>>> frozen_dict = frozendict({'x': 3, 'y': 4, 'z': {'a': 0, 'b': [3,1,{4,1},[5,9]]}}, c= 1)
>>> dict = dict({'x': 3, 'y': 4, 'z': {'a': 0, 'b': [3,1,{4,1},[5,9]]}}, c= 1)

# comparaison
>>> import sys
>>> tuple(map(sys.getsizeof, [frozen_dict, my_frozen_dict, dict]))
(248, 240, 232)

Notice my_frozen_dict takes less space in memory than frozen_dict!

🎉 Credits

The following projects were used to build and test frozndict.

• python
• poetry
• pytest
• flake8
• coverage
• rstcheck
• mypy
• pytestcov
• tox
• isort
• black
• precommit

👋 Contribute

If you are looking for a way to contribute to the project, please refer to the Guideline.

📝 License

This program and the accompanying materials are made available under the terms and conditions of the GNU GENERAL PUBLIC LICENSE.