glom

Restructuring data, the Python way

Real applications have real data, and real data nests. Objects inside of objects inside of lists of objects.

glom is a powerful way to handle real-world data, featuring:

• Path-based access for nested data structures
• Readable, meaningful error messages
• Declarative data transformation, using lightweight, Pythonic specifications
• Built-in data exploration and debugging features

pip install glom

And when you install glom, you also get [the glom command-line interface][cli_rtd], letting you experiment at the console, but never limiting you to shell scripts:

Usage: glom [FLAGS] [spec [target]]
Command-line interface to the glom library, providing nested data access and data restructuring with the power of Python.
Flags:
--help / -h                     show this help message and exit   --target-file TARGET_FILE       path to target data source (optional)   --target-format TARGET_FORMAT                                   format of the source data (json, python, toml,                                   or yaml) (defaults to 'json')   --spec-file SPEC_FILE           path to glom spec definition (optional)   --spec-format SPEC_FORMAT       format of the glom spec definition (json, python,                                     python-full) (defaults to 'python')   --indent INDENT                 number of spaces to indent the result, 0 to disable                                     pretty-printing (defaults to 2)   --debug                         interactively debug any errors that come up   --inspect                       interactively explore the data

Anything you can do at the command line readily translates to Python code, so you've always got a path forward when complexity starts to ramp up.

Examples

Without glom

>>> data = {'a': {'b': {'c': 'd'}}}
>>> data['a']['b']['c']
'd'
>>> data2 = {'a': {'b': None}}
>>> data2['a']['b']['c']
Traceback (most recent call last):
...
TypeError: 'NoneType' object is not subscriptable

With glom

>>> glom(data, 'a.b.c')
'd'
>>> glom(data2, 'a.b.c')
Traceback (most recent call last):
...
PathAccessError: could not access 'c', index 2 in path Path('a', 'b', 'c'), got error: ...

Learn more

If all this seems interesting, continue exploring glom below:

• [glom Tutorial][tutorial]
• [Full API documentation at Read the Docs][rtd]
• [Original announcement blog post (2018-05-09)][glom_announce]
• [Frequently Asked Questions][faq]
• [PyCon 2018 Lightning Talk (2018-05-11)][pycon_talk]
• [Try glom in your browser (glompad)][glompad]

[rtd]: https://glom.readthedocs.io [cli_rtd]: https://glom.readthedocs.io/en/latest/cli.html [tutorial]: https://glom.readthedocs.io/en/latest/tutorial.html [faq]: https://glom.readthedocs.io/en/latest/faq.html [glomannounce]: https://sedimental.org/glomrestructured_data.html [gh_issues]: https://github.com/mahmoud/glom/issues/ [pycon_talk]: https://www.youtube.com/watch?v=bTAFl8P2DkE&t=18m07s [glompad]: https://yak.party/glompad/

In the meantime, just remember: When you've got nested data, glom it! ☄️