Mutation

Some in-place modifications are available:

# Tree
tree.add(data, ...)
...
# Node
node.add(data, ...)
node.prepend_child(data, ...)
...
node.move_to(new_parent, before)
node.sort_children()

# Delete nodes
node.remove()
node.remove_children()
# del will call `remove()`
del tree["A"]
tree.clear()
tree.filter(...)

# Append a copy of branch 'b1' to 'a1'
tree["a1"].add(tree["b1"])

Filtering, copy, and diff operations usually return the result as a new tree instance:

def pred(node):
    # Return true to include `node` and its children
    return node.data.age >= 18

tree_2 = tree.copy(predicate=pred)

assert tree_2.first_node is not tree.first_node        # different nodes...
assert tree_2.first_node.data is tree.first_node.data  # ... reference the same data
assert tree_2.first_node == tree.first_node            # and evaluate as 'equal'

See also

Some methods accept callbacks to control node selection, for example copy(), filter(), find(), find_all(), find_first(), visit(), …

See Iteration Callbacks for details.