# Copyright 2018-2021
# Institute of Neuroscience and Medicine (INM-1), Forschungszentrum Jülich GmbH

# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at

#     http://www.apache.org/licenses/LICENSE-2.0

# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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"""
Explore brain region hierarchies
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Each parcellation is the root element of a tree of brain regions.
In fact, Parcellation objects are special Region objects, so they
inherit all functionalities of a region, while providing additional
capabilities such as access to parcellation maps. 
Other then "standard" Region objects, parcellations do not have a
parent region.
"""

# %%
# We start by selecting an atlas and a parcellation
import siibra
atlas = siibra.atlases.get('human')
julich_brain = atlas.parcellations.get('julich 2.9')
julich_brain
# sphinx_gallery_thumbnail_path = '_static/example_thumbnails/01-002.png'

# %%
# The region hierarchy is a tree structure. Its default representation is a string of the tree.
print(julich_brain.tree2str())

# %%
# Each node is a `Region` object, including the root node.
# We can iterate all regions in a parcellation
[region.name for region in julich_brain]

# %%
# We can iterate the brain divisions in the parcellation
[region.name for region in julich_brain.children]

# %%
# We can also iterate only the leaves of the tree
[region.name for region in julich_brain.leaves]