LFake 18.9.0
Fake data
License: MIT License
Requires Python: >=3.7
Keywords: Lfake fixtures data test mock generator

*Faker* is a Python package that generates fake data for you. Whether
you need to bootstrap your database, create good-looking XML documents,
fill-in your persistence to stress test it, or anonymize data taken from
a production service, Faker is for you.

Faker is heavily inspired by `PHP Faker`_, `Perl Faker`_, and by `Ruby Faker`_.

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Compatibility
-------------

Starting from version ``4.0.0``, ``Faker`` dropped support for Python 2 and from version ``5.0.0``
only supports Python 3.7 and above. If you still need Python 2 compatibility, please install version ``3.0.1`` in the
meantime, and please consider updating your codebase to support Python 3 so you can enjoy the
latest features ``Faker`` has to offer. Please see the `extended docs`_ for more details, especially
if you are upgrading from version ``2.0.4`` and below as there might be breaking changes.

This package was also previously called ``fake-factory`` which was already deprecated by the end
of 2016, and much has changed since then, so please ensure that your project and its dependencies
do not depend on the old package.

Basic Usage
-----------

Install with pip:

.. code:: bash

    pip install Faker

Use ``faker.Faker()`` to create and initialize a faker
generator, which can generate data by accessing properties named after
the type of data you want.

.. code:: python

    from faker import Faker
    fake = Faker()

    fake.name()
    # 'Lucy Cechtelar'

    fake.address()
    # '426 Jordy Lodge
    #  Cartwrightshire, SC 88120-6700'

    fake.text()
    # 'Sint velit eveniet. Rerum atque repellat voluptatem quia rerum. Numquam excepturi
    #  beatae sint laudantium consequatur. Magni occaecati itaque sint et sit tempore. Nesciunt
    #  amet quidem. Iusto deleniti cum autem ad quia aperiam.
    #  A consectetur quos aliquam. In iste aliquid et aut similique suscipit. Consequatur qui
    #  quaerat iste minus hic expedita. Consequuntur error magni et laboriosam. Aut aspernatur
    #  voluptatem sit aliquam. Dolores voluptatum est.
    #  Aut molestias et maxime. Fugit autem facilis quos vero. Eius quibusdam possimus est.
    #  Ea quaerat et quisquam. Deleniti sunt quam. Adipisci consequatur id in occaecati.
    #  Et sint et. Ut ducimus quod nemo ab voluptatum.'

Each call to method ``fake.name()`` yields a different (random) result.
This is because faker forwards ``faker.Generator.method_name()`` calls
to ``faker.Generator.format(method_name)``.

.. code:: python

    for _ in range(10):
      print(fake.name())

    # 'Adaline Reichel'
    # 'Dr. Santa Prosacco DVM'
    # 'Noemy Vandervort V'
    # 'Lexi O'Conner'
    # 'Gracie Weber'
    # 'Roscoe Johns'
    # 'Emmett Lebsack'
    # 'Keegan Thiel'
    # 'Wellington Koelpin II'
    # 'Ms. Karley Kiehn V'

Pytest fixtures
---------------

``Faker`` also has its own ``pytest`` plugin which provides a ``faker`` fixture you can use in your
tests. Please check out the `pytest fixture docs` to learn more.

Providers
---------

Each of the generator properties (like ``name``, ``address``, and
``lorem``) are called "fake". A faker generator has many of them,
packaged in "providers".

.. code:: python

    from faker import Faker
    from faker.providers import internet

    fake = Faker()
    fake.add_provider(internet)

    print(fake.ipv4_private())


Check the `extended docs`_ for a list of `bundled providers`_ and a list of
`community providers`_.

Localization
------------

``faker.Faker`` can take a locale as an argument, to return localized
data. If no localized provider is found, the factory falls back to the
default LCID string for US english, ie: ``en_US``.

.. code:: python

    from faker import Faker
    fake = Faker('it_IT')
    for _ in range(10):
        print(fake.name())

    # 'Elda Palumbo'
    # 'Pacifico Giordano'
    # 'Sig. Avide Guerra'
    # 'Yago Amato'
    # 'Eustachio Messina'
    # 'Dott. Violante Lombardo'
    # 'Sig. Alighieri Monti'
    # 'Costanzo Costa'
    # 'Nazzareno Barbieri'
    # 'Max Coppola'

``faker.Faker`` also supports multiple locales. New in v3.0.0.

.. code:: python

    from faker import Faker
    fake = Faker(['it_IT', 'en_US', 'ja_JP'])
    for _ in range(10):
        print(fake.name())

    # 鈴木 陽一
    # Leslie Moreno
    # Emma Williams
    # 渡辺 裕美子
    # Marcantonio Galuppi
    # Martha Davis
    # Kristen Turner
    # 中津川 春香
    # Ashley Castillo
    # 山田 桃子

You can check available Faker locales in the source code, under the
providers package. The localization of Faker is an ongoing process, for
which we need your help. Please don't hesitate to create a localized
provider for your own locale and submit a Pull Request (PR).

Optimizations
-------------
The Faker constructor takes a performance-related argument called
``use_weighting``. It specifies whether to attempt to have the frequency
of values match real-world frequencies (e.g. the English name Gary would
be much more frequent than the name Lorimer). If ``use_weighting`` is ``False``,
then all items have an equal chance of being selected, and the selection
process is much faster. The default is ``True``.

Command line usage
------------------

When installed, you can invoke faker from the command-line:

.. code:: console

    faker [-h] [--version] [-o output]
          [-l {bg_BG,cs_CZ,...,zh_CN,zh_TW}]
          [-r REPEAT] [-s SEP]
          [-i {package.containing.custom_provider otherpkg.containing.custom_provider}]
          [fake] [fake argument [fake argument ...]]

Where:

-  ``faker``: is the script when installed in your environment, in
   development you could use ``python -m faker`` instead

-  ``-h``, ``--help``: shows a help message

-  ``--version``: shows the program's version number

-  ``-o FILENAME``: redirects the output to the specified filename

-  ``-l {bg_BG,cs_CZ,...,zh_CN,zh_TW}``: allows use of a localized
   provider

-  ``-r REPEAT``: will generate a specified number of outputs

-  ``-s SEP``: will generate the specified separator after each
   generated output

-  ``-i {my.custom_provider other.custom_provider}`` list of additional custom
   providers to use. Note that is the import path of the package containing
   your Provider class, not the custom Provider class itself.

-  ``fake``: is the name of the fake to generate an output for, such as
   ``name``, ``address``, or ``text``

-  ``[fake argument ...]``: optional arguments to pass to the fake (e.g. the
   profile fake takes an optional list of comma separated field names as the
   first argument)

Examples:

.. code:: console

    $ faker address
    968 Bahringer Garden Apt. 722
    Kristinaland, NJ 09890

    $ faker -l de_DE address
    Samira-Niemeier-Allee 56
    94812 Biedenkopf

    $ faker profile ssn,birthdate
    {'ssn': '628-10-1085', 'birthdate': '2008-03-29'}

    $ faker -r=3 -s=";" name
    Willam Kertzmann;
    Josiah Maggio;
    Gayla Schmitt;

How to create a Provider
------------------------

.. code:: python

    from faker import Faker
    fake = Faker()

    # first, import a similar Provider or use the default one
    from faker.providers import BaseProvider

    # create new provider class
    class MyProvider(BaseProvider):
        def foo(self) -> str:
            return 'bar'

    # then add new provider to faker instance
    fake.add_provider(MyProvider)

    # now you can use:
    fake.foo()
    # 'bar'


How to create a Dynamic Provider
--------------------------------

Dynamic providers can read elements from an external source.

.. code:: python

    from faker import Faker
    from faker.providers import DynamicProvider

    medical_professions_provider = DynamicProvider(
         provider_name="medical_profession",
         elements=["dr.", "doctor", "nurse", "surgeon", "clerk"],
    )

    fake = Faker()

    # then add new provider to faker instance
    fake.add_provider(medical_professions_provider)

    # now you can use:
    fake.medical_profession()
    # 'dr.'

How to customize the Lorem Provider
-----------------------------------

You can provide your own sets of words if you don't want to use the
default lorem ipsum one. The following example shows how to do it with a list of words picked from `cakeipsum <http://www.cupcakeipsum.com/>`__ :

.. code:: python

    from faker import Faker
    fake = Faker()

    my_word_list = [
    'danish','cheesecake','sugar',
    'Lollipop','wafer','Gummies',
    'sesame','Jelly','beans',
    'pie','bar','Ice','oat' ]

    fake.sentence()
    # 'Expedita at beatae voluptatibus nulla omnis.'

    fake.sentence(ext_word_list=my_word_list)
    # 'Oat beans oat Lollipop bar cheesecake.'


How to use with Factory Boy
---------------------------

`Factory Boy` already ships with integration with ``Faker``. Simply use the
``factory.Faker`` method of ``factory_boy``:

.. code:: python

    import factory
    from myapp.models import Book

    class BookFactory(factory.Factory):
        class Meta:
            model = Book

        title = factory.Faker('sentence', nb_words=4)
        author_name = factory.Faker('name')

Accessing the `random` instance
-------------------------------

The ``.random`` property on the generator returns the instance of
``random.Random`` used to generate the values:

.. code:: python

    from faker import Faker
    fake = Faker()
    fake.random
    fake.random.getstate()

By default all generators share the same instance of ``random.Random``, which
can be accessed with ``from faker.generator import random``. Using this may
be useful for plugins that want to affect all faker instances.

Unique values
-------------

Through use of the ``.unique`` property on the generator, you can guarantee
that any generated values are unique for this specific instance.

.. code:: python

   from faker import Faker
   fake = Faker()
   names = [fake.unique.first_name() for i in range(500)]
   assert len(set(names)) == len(names)

Calling ``fake.unique.clear()`` clears the already seen values.
Note, to avoid infinite loops, after a number of attempts to find a unique
value, Faker will throw a ``UniquenessException``. Beware of the `birthday
paradox <https://en.wikipedia.org/wiki/Birthday_problem>`_, collisions
are more likely than you'd think.


.. code:: python

   from faker import Faker

   fake = Faker()
   for i in range(3):
        # Raises a UniquenessException
        fake.unique.boolean()

In addition, only hashable arguments and return values can be used
with ``.unique``.

Seeding the Generator
---------------------

When using Faker for unit testing, you will often want to generate the same
data set. For convenience, the generator also provide a ``seed()`` method,
which seeds the shared random number generator. Seed produces the same result
when the same methods with the same version of faker are called.

.. code:: python

    from faker import Faker
    fake = Faker()
    Faker.seed(4321)

    print(fake.name())
    # 'Margaret Boehm'

Each generator can also be switched to its own instance of ``random.Random``,
separate to the shared one, by using the ``seed_instance()`` method, which acts
the same way. For example:

.. code:: python

    from faker import Faker
    fake = Faker()
    fake.seed_instance(4321)

    print(fake.name())
    # 'Margaret Boehm'

Please note that as we keep updating datasets, results are not guaranteed to be
consistent across patch versions. If you hardcode results in your test, make sure
you pinned the version of ``Faker`` down to the patch number.

If you are using ``pytest``, you can seed the ``faker`` fixture by defining a ``faker_seed``
fixture. Please check out the `pytest fixture docs` to learn more.

Tests
-----

Run tests:

.. code:: bash

    $ tox

Write documentation for the providers of the default locale:

.. code:: bash

    $ python -m faker > docs.txt

Write documentation for the providers of a specific locale:

.. code:: bash

    $ python -m faker --lang=de_DE > docs_de.txt


Contribute
----------

Please see `CONTRIBUTING`_.

License
-------

Faker is released under the MIT License. See the bundled `LICENSE`_ file
for details.

Credits
-------

-  `FZaninotto`_ / `PHP Faker`_
-  `Distribute`_
-  `Buildout`_
-  `modern-package-template`_


.. _FZaninotto: https://github.com/fzaninotto
.. _PHP Faker: https://github.com/fzaninotto/Faker
.. _Perl Faker: http://search.cpan.org/~jasonk/Data-Faker-0.07/
.. _Ruby Faker: https://github.com/stympy/faker
.. _Distribute: https://pypi.org/project/distribute/
.. _Buildout: http://www.buildout.org/
.. _modern-package-template: https://pypi.org/project/modern-package-template/
.. _extended docs: https://faker.readthedocs.io/en/stable/
.. _bundled providers: https://faker.readthedocs.io/en/stable/providers.html
.. _community providers: https://faker.readthedocs.io/en/stable/communityproviders.html
.. _pytest fixture docs: https://faker.readthedocs.io/en/master/pytest-fixtures.html
.. _LICENSE: https://github.com/joke2k/faker/blob/master/LICENSE.txt
.. _CONTRIBUTING: https://github.com/joke2k/faker/blob/master/CONTRIBUTING.rst
.. _Factory Boy: https://github.com/FactoryBoy/factory_boy

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