Multiple Instances (‘Clones’)

Every Node instance is unique within the tree and also has a unique node.node_id value.

However, one data object may be added multiple times to a tree at different locations:

Tree<'multi'>
├── 'A'
│   ├── 'a1'
│   ╰── 'a2'
╰── 'B'
    ├── 'b1'
    ╰── 'a2'  <- 2nd occurrence

See also

Clones have several appliances in the real world, for example store items may be listed in different categories, or files may be linked into multiple parent folders.

When a tree is used to visualize a directed graph, clones are used to represent a node that is connected by multiple edges. See Graphs for an example.

Note

Multiple instances must not appear under the same parent node.

In this case, a lookup using the indexing syntax (tree[data]) is not allowed.
Use tree.Tree.find_first() or find_all() instead.

find_first() will return the first match (or None). Note that find() is an alias for find_first():

print(tree.find("a2"))

Node<'a2', data_id=-942131188891065821>

find_all() will return all matches (or an empty array []):

res = tree.find_all("a2")
assert res[0] is not res[1], "Node instances are NOT identical..."
assert res[0] == res[1],     "... but evaluate as equal."
assert res[0].parent.name == "A"
assert res[1].parent.name == "B"
assert res[0].data is res[1].data, "A single data object instance is referenced by both nodes"

print(res)

[Node<'a2', data_id=-942131188891065821>, Node<'a2', data_id=-942131188891065821>]