joke2k/faker — 19.3k Stars

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#dataset #fake #fake-data #faker #faker-generator #python #test-data #test-data-generator #testing

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README

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 3.8 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(['itIT', 'enUS', '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 {bgBG,csCZ,...,zhCN,zhTW}]           [-r REPEAT] [-s SEP]           [-i package.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 {bgBG,csCZ,...,zhCN,zhTW}: 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 package.containing.custom_provider additional custom provider to use. Note this

   is the import path of the package containing your Provider class, not the
   custom Provider class itself. Can be repeated to add multiple providers.

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;
$ faker -i fakercreditscore creditscorefull     Experian/Fair Isaac Risk Model V2SM     Experian     801
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
medicalprofessionsprovider = DynamicProvider(          providername="medicalprofession",          elements=["dr.", "doctor", "nurse", "surgeon", "clerk"],     )
fake = Faker()
# then add new provider to faker instance     fake.addprovider(medicalprofessions_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 __ :


.. code:: python
from faker import Faker     fake = Faker()
mywordlist = [     'danish','cheesecake','sugar',     'Lollipop','wafer','Gummies',     'sesame','Jelly','beans',     'pie','bar','Ice','oat' ]
fake.sentence()     # 'Expedita at beatae voluptatibus nulla omnis.'
fake.sentence(extwordlist=mywordlist)     # '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)

On Faker instances with multiple locales, you can specify the locale to use for the unique values by using the subscript notation:


.. code:: python
from faker import Faker    fake = Faker(['enUS', 'frFR'])    names = [fake.unique["enUS"].firstname() 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 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 provides a seed() method, which seeds the shared random number generator. A 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 use its own instance of random.Random, separated from 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=deDE > docsde.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: https://metacpan.org/dist/Data-Faker .. _Ruby Faker: https://github.com/stympy/faker .. _Distribute: https://pypi.org/project/distribute/ .. _Buildout: https://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/stable/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/factoryboy

.. |pypi| image:: https://img.shields.io/pypi/v/Faker.svg?style=flat-square&label=version :target: https://pypi.org/project/Faker/ :alt: Latest version released on PyPI

.. |coverage| image:: https://img.shields.io/coveralls/joke2k/faker/master.svg?style=flat-square :target: https://coveralls.io/r/joke2k/faker?branch=master :alt: Test coverage

.. |build| image:: https://github.com/joke2k/faker/actions/workflows/ci.yml/badge.svg :target: https://github.com/joke2k/faker/actions/workflows/ci.yml :alt: Build status of the master branch

.. |license| image:: https://img.shields.io/badge/license-MIT-blue.svg?style=flat-square :target: https://raw.githubusercontent.com/joke2k/faker/master/LICENSE.txt :alt: Package license

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