Fixed database typo and removed unnecessary class identifier.

venv/Lib/site-packages/networkx/readwrite/json_graph/tree.py

@@ -0,0 +1,146 @@
+from itertools import chain
+import networkx as nx
+
+__all__ = ["tree_data", "tree_graph"]
+
+_attrs = dict(id="id", children="children")
+
+
+def tree_data(G, root, attrs=_attrs):
+    """Returns data in tree format that is suitable for JSON serialization
+    and use in Javascript documents.
+
+    Parameters
+    ----------
+    G : NetworkX graph
+       G must be an oriented tree
+
+    root : node
+       The root of the tree
+
+    attrs : dict
+        A dictionary that contains two keys 'id' and 'children'. The
+        corresponding values provide the attribute names for storing
+        NetworkX-internal graph data. The values should be unique. Default
+        value: :samp:`dict(id='id', children='children')`.
+
+        If some user-defined graph data use these attribute names as data keys,
+        they may be silently dropped.
+
+    Returns
+    -------
+    data : dict
+       A dictionary with node-link formatted data.
+
+    Raises
+    ------
+    NetworkXError
+        If values in attrs are not unique.
+
+    Examples
+    --------
+    >>> from networkx.readwrite import json_graph
+    >>> G = nx.DiGraph([(1, 2)])
+    >>> data = json_graph.tree_data(G, root=1)
+
+    To serialize with json
+
+    >>> import json
+    >>> s = json.dumps(data)
+
+    Notes
+    -----
+    Node attributes are stored in this format but keys
+    for attributes must be strings if you want to serialize with JSON.
+
+    Graph and edge attributes are not stored.
+
+    The default value of attrs will be changed in a future release of NetworkX.
+
+    See Also
+    --------
+    tree_graph, node_link_data, node_link_data
+    """
+    if G.number_of_nodes() != G.number_of_edges() + 1:
+        raise TypeError("G is not a tree.")
+    if not G.is_directed():
+        raise TypeError("G is not directed.")
+
+    id_ = attrs["id"]
+    children = attrs["children"]
+    if id_ == children:
+        raise nx.NetworkXError("Attribute names are not unique.")
+
+    def add_children(n, G):
+        nbrs = G[n]
+        if len(nbrs) == 0:
+            return []
+        children_ = []
+        for child in nbrs:
+            d = dict(chain(G.nodes[child].items(), [(id_, child)]))
+            c = add_children(child, G)
+            if c:
+                d[children] = c
+            children_.append(d)
+        return children_
+
+    data = dict(chain(G.nodes[root].items(), [(id_, root)]))
+    data[children] = add_children(root, G)
+    return data
+
+
+def tree_graph(data, attrs=_attrs):
+    """Returns graph from tree data format.
+
+    Parameters
+    ----------
+    data : dict
+        Tree formatted graph data
+
+    Returns
+    -------
+    G : NetworkX DiGraph
+
+    attrs : dict
+        A dictionary that contains two keys 'id' and 'children'. The
+        corresponding values provide the attribute names for storing
+        NetworkX-internal graph data. The values should be unique. Default
+        value: :samp:`dict(id='id', children='children')`.
+
+    Examples
+    --------
+    >>> from networkx.readwrite import json_graph
+    >>> G = nx.DiGraph([(1, 2)])
+    >>> data = json_graph.tree_data(G, root=1)
+    >>> H = json_graph.tree_graph(data)
+
+    Notes
+    -----
+    The default value of attrs will be changed in a future release of NetworkX.
+
+    See Also
+    --------
+    tree_graph, node_link_data, adjacency_data
+    """
+    graph = nx.DiGraph()
+    id_ = attrs["id"]
+    children = attrs["children"]
+
+    def add_children(parent, children_):
+        for data in children_:
+            child = data[id_]
+            graph.add_edge(parent, child)
+            grandchildren = data.get(children, [])
+            if grandchildren:
+                add_children(child, grandchildren)
+            nodedata = {
+                str(k): v for k, v in data.items() if k != id_ and k != children
+            }
+            graph.add_node(child, **nodedata)
+
+    root = data[id_]
+    children_ = data.get(children, [])
+    nodedata = {str(k): v for k, v in data.items() if k != id_ and k != children}
+    graph.add_node(root, **nodedata)
+    add_children(root, children_)
+    return graph