Skip to main content

A flexible utility for flattening dict-like objects in Python.

Project description

Please visit the GitHub repository for more information.


A flexible utility for flattening dict-like objects in Python.


This Python package provide a function flatten() for flattening dict-like objects. It also provides some key joining methods (reducer), and you can choose the reducer you want or even implement your own reducer. You can also choose to invert the resulting flat dict.


def flatten(d, reducer='tuple', inverse=False):
    """Flatten dict-like object.

    d: dict-like object
        The dict that will be flattened.
    reducer: {'tuple', 'path', function} (default: 'tuple')
        The key joining method. If a function is given, the function will be
        used to reduce.
        'tuple': The resulting key will be tuple of the original keys
        'path': Use ``os.path.join`` to join keys.
    inverse: bool (default: False)
        Whether you want invert the resulting key and value.

    flat_dict: dict


In [1]: from flatten_dict import flatten

In [2]: normal_dict = {
   ...:     'a': '0',
   ...:     'b': {
   ...:         'a': '1.0',
   ...:         'b': '1.1',
   ...:     },
   ...:     'c': {
   ...:         'a': '2.0',
   ...:         'b': {
   ...:             'a': '2.1.0',
   ...:             'b': '2.1.1',
   ...:         },
   ...:     },
   ...: }

In [3]: flatten(normal_dict)
{('a',): '0',
 ('b', 'a'): '1.0',
 ('b', 'b'): '1.1',
 ('c', 'a'): '2.0',
 ('c', 'b', 'a'): '2.1.0',
 ('c', 'b', 'b'): '2.1.1'}

In [4]: flatten(normal_dict, reducer='path')
{'a': '0',
 'b/a': '1.0',
 'b/b': '1.1',
 'c/a': '2.0',
 'c/b/a': '2.1.0',
 'c/b/b': '2.1.1'}

In [5]: flatten(normal_dict, reducer='path', inverse=True)
{'0': 'a',
 '1.0': 'b/a',
 '1.1': 'b/b',
 '2.0': 'c/a',
 '2.1.0': 'c/b/a',
 '2.1.1': 'c/b/b'}

In [6]: def underscore_reducer(k1, k2):
   ...:     if k1 is None:
   ...:         return k2
   ...:     else:
   ...:         return k1 + "_" + k2

In [7]: flatten(normal_dict, reducer=underscore_reducer)
{'a': '0',
 'b_a': '1.0',
 'b_b': '1.1',
 'c_a': '2.0',
 'c_b_a': '2.1.0',
 'c_b_b': '2.1.1'}

Project details

Download files

Download the file for your platform. If you're not sure which to choose, learn more about installing packages.

Source Distribution

flatten-dict-0.0.3.tar.gz (4.0 kB view hashes)

Uploaded source

Built Distribution

flatten_dict-0.0.3-py2.py3-none-any.whl (4.7 kB view hashes)

Uploaded py2 py3

Supported by

AWS AWS Cloud computing Datadog Datadog Monitoring Fastly Fastly CDN Google Google Object Storage and Download Analytics Microsoft Microsoft PSF Sponsor Pingdom Pingdom Monitoring Sentry Sentry Error logging StatusPage StatusPage Status page