tree is a library for working with nested data structures. In a way, tree generalizes the builtin map function which only supports flat sequences, and allows to apply a function to each "leaf" preserving the overall structure.

>>> import tree
>>> structure = [[1], [[[2, 3]]], [4]]
>>> tree.flatten(structure)
[1, 2, 3, 4]
>>> tree.map_structure(lambda v: v**2, structure)
[[1], [[[4, 9]]], [16]]

tree is backed by an optimized C++ implementation suitable for use in demanding applications, such as machine learning models.

From PyPI:

$ pip install dm-tree

Directly from github using pip:

$ pip install git+git://github.com/deepmind/tree.git

Build from source:

$ python setup.py install

If you are having issues, please let us know by filing an issue on our issue tracker.

The project is licensed under the Apache 2.0 license.