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# fiftyone.core.annotation.nodes

Taxonomy node primitive.

Copyright 2017-2026, Voxel51, Inc.
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[voxel51.com](https://voxel51.com/)
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**Classes:**

| [`Node`](#fiftyone.core.annotation.nodes.Node)(name[, description, can_select, ...])   | A node in a [`fiftyone.core.ontology.Taxonomy`](fiftyone.core.ontology.md#fiftyone.core.ontology.Taxonomy) tree.   |
|----------------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------|

**Functions:**

| [`find_in_dict`](#fiftyone.core.annotation.nodes.find_in_dict)(root, name)    | Returns the first descendant (or `root` itself) whose `name` matches, or `None`.   |
|-------------------------------------------------------------------------------|------------------------------------------------------------------------------------|
| [`truncate_dict`](#fiftyone.core.annotation.nodes.truncate_dict)(node, depth) | Returns a copy of `node` truncated to `depth` levels below.                        |

### *class* fiftyone.core.annotation.nodes.Node(name: str, description: str | None = None, can_select: [bool](fiftyone.core.stages.md#fiftyone.core.stages.Exists.bool) = True, deprecated: [bool](fiftyone.core.stages.md#fiftyone.core.stages.Exists.bool) = False, values: [list](fiftyone.core.session.events.md#fiftyone.core.session.events.Colorscale.list)[[Node](#fiftyone.core.annotation.nodes.Node)] | None = None)

Bases: `object`

A node in a [`fiftyone.core.ontology.Taxonomy`](fiftyone.core.ontology.md#fiftyone.core.ontology.Taxonomy) tree.

There is a single node type: every node has the same shape regardless
of whether it represents a leaf class, a sub-class, or a group header.
The role of a node is determined by its position in the tree and by
the `can_select` flag.

* **Parameters:**
  * **name** – required label for this node — a class name, sub-class
    name, or group header. Must be unique within the taxonomy
    (uniqueness is enforced by `validate_taxonomy`, not at
    construction time).
  * **description** – optional context for the user (tooltip / guidance
    text in the UI)
  * **can_select** – if `False`, the node is a group header — it
    expands to show child nodes but is not itself selectable as
    a class. Defaults to `True`.
  * **deprecated** – if `True`, the node is hidden from the UI for new
    selections but remains valid on existing labels. Defaults to
    `False`.
  * **values** – optional list of child [`Node`](#fiftyone.core.annotation.nodes.Node) instances. A leaf
    node has no `values`; a node with children has `values`.

Example:

```default
Node(
    name="vehicles",
    can_select=False,
    values=[
        Node(name="car"),
        Node(name="truck"),
    ],
)
```

**Attributes:**

| [`name`](#fiftyone.core.annotation.nodes.Node.name)               |    |
|-------------------------------------------------------------------|----|
| [`description`](#fiftyone.core.annotation.nodes.Node.description) |    |
| [`can_select`](#fiftyone.core.annotation.nodes.Node.can_select)   |    |
| [`deprecated`](#fiftyone.core.annotation.nodes.Node.deprecated)   |    |
| [`values`](#fiftyone.core.annotation.nodes.Node.values)           |    |

**Methods:**

| [`to_dict`](#fiftyone.core.annotation.nodes.Node.to_dict)()      | Serializes this node to a dict.                                       |
|------------------------------------------------------------------|-----------------------------------------------------------------------|
| [`from_dict`](#fiftyone.core.annotation.nodes.Node.from_dict)(d) | Creates a [`Node`](#fiftyone.core.annotation.nodes.Node) from a dict. |

#### name *: str*

#### description *: str | None* *= None*

#### can_select *: [bool](fiftyone.core.stages.md#fiftyone.core.stages.Exists.bool)* *= True*

#### deprecated *: [bool](fiftyone.core.stages.md#fiftyone.core.stages.Exists.bool)* *= False*

#### values *: [list](fiftyone.core.session.events.md#fiftyone.core.session.events.Colorscale.list)[[Node](#fiftyone.core.annotation.nodes.Node)] | None* *= None*

#### to_dict() → dict

Serializes this node to a dict.

* **Returns:**
  a dict

#### *classmethod* from_dict(d: dict) → [Node](#fiftyone.core.annotation.nodes.Node)

Creates a [`Node`](#fiftyone.core.annotation.nodes.Node) from a dict.

* **Parameters:**
  **d** – a node dict
* **Returns:**
  a [`Node`](#fiftyone.core.annotation.nodes.Node)

### fiftyone.core.annotation.nodes.find_in_dict(root: dict, name: str) → dict | None

Returns the first descendant (or `root` itself) whose `name`
matches, or `None`.

Node names are unique within a taxonomy (enforced by
[`fiftyone.core.ontology_validation.validate_taxonomy()`](fiftyone.core.ontology_validation.md#fiftyone.core.ontology_validation.validate_taxonomy)), so the
first match is the only match.

* **Parameters:**
  * **root** – a node-shaped dict
  * **name** – the node name to search for
* **Returns:**
  the matching dict (a reference into `root`) or `None`

### fiftyone.core.annotation.nodes.truncate_dict(node: dict, depth: int) → dict

Returns a copy of `node` truncated to `depth` levels below.

At the truncation boundary, nodes that had children in the source
are returned with `values=[]` so the wire format distinguishes
them from real leaves (which have no `values` key).

* **Parameters:**
  * **node** – a node-shaped dict
  * **depth** – non-negative recursion depth. `0` returns just
    `node` with no descendants.
* **Returns:**
  a new dict; the input is not mutated