YAML Import/Export

YAML (YAML Ain’t Markup Language) is a human-readable data serialization language.

PYYAML implements importer and exporter in python. Please install it, before continuing


anytree package does not depend on any external packages. It does NOT include PYYAML.


It is not safe to call yaml.load with any data received from an untrusted source! yaml.load is as powerful as pickle.load and so may call any Python function. The yaml.safe_load function limits the load functionality to built-in types.


The DictExporter converts any tree to a dictionary, which can be handled by yaml.dump.

>>> import yaml
>>> from anytree import AnyNode
>>> from anytree.exporter import DictExporter

Example tree:

>>> root = AnyNode(a="root")
>>> s0 = AnyNode(a="sub0", parent=root)
>>> s0a = AnyNode(a="sub0A", b="foo", parent=s0)
>>> s0b = AnyNode(a="sub0B", parent=s0)
>>> s1 = AnyNode(a="sub1", parent=root)

Export to dictionary and convert to YAML:

>>> dct = DictExporter().export(root)
>>> print(yaml.dump(dct, default_flow_style=False))
a: root
- a: sub0
  - a: sub0A
    b: foo
  - a: sub0B
- a: sub1

DictExporter controls the content. yaml.dump controls the YAML related stuff.

To dump to a file, use an file object as second argument:

>>> with open("/path/to/file", "w") as file:  # doctest: +SKIP
...     yaml.dump(data, file)


The yaml.load function reads YAML data — a dictionary, which DictImporter converts to a tree.

>>> import yaml
>>> from anytree.importer import DictImporter
>>> from pprint import pprint  # just for nice printing
>>> from anytree import RenderTree  # just for nice printing

Example data:

>>> data = """
... a: root
... children:
... - a: sub0
...   children:
...   - a: sub0A
...     b: foo
...   - a: sub0B
... - a: sub1
... """

Import to dictionary and convert to tree:

>>> dct = yaml.load(data)
>>> pprint(dct)
{'a': 'root',
 'children': [{'a': 'sub0',
               'children': [{'a': 'sub0A', 'b': 'foo'}, {'a': 'sub0B'}]},
              {'a': 'sub1'}]}
>>> root = DictImporter().import_(dct)
>>> print(RenderTree(root))
├── AnyNode(a='sub0')
│   ├── AnyNode(a='sub0A', b='foo')
│   └── AnyNode(a='sub0B')
└── AnyNode(a='sub1')