Source code for networkx.readwrite.json_graph.tree

from itertools import chain

import networkx as nx

__all__ = ["tree_data", "tree_graph"]


[docs]def tree_data(G, root, ident="id", children="children"): """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 ident : string Attribute name for storing NetworkX-internal graph data. `ident` must have a different value than `children`. The default is 'id'. children : string Attribute name for storing NetworkX-internal graph data. `children` must have a different value than `ident`. The default is 'children'. Returns ------- data : dict A dictionary with node-link formatted data. Raises ------ NetworkXError If `children` and `ident` attributes are identical. 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. See Also -------- tree_graph, node_link_data, adjacency_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.") if not nx.is_weakly_connected(G): raise TypeError("G is not weakly connected.") if ident == children: raise nx.NetworkXError("The values for `id` and `children` must be different.") 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(), [(ident, child)])) c = add_children(child, G) if c: d[children] = c children_.append(d) return children_ data = dict(chain(G.nodes[root].items(), [(ident, root)])) data[children] = add_children(root, G) return data
[docs]def tree_graph(data, ident="id", children="children"): """Returns graph from tree data format. Parameters ---------- data : dict Tree formatted graph data ident : string Attribute name for storing NetworkX-internal graph data. `ident` must have a different value than `children`. The default is 'id'. children : string Attribute name for storing NetworkX-internal graph data. `children` must have a different value than `ident`. The default is 'children'. Returns ------- G : NetworkX DiGraph 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) See Also -------- tree_data, node_link_data, adjacency_data """ graph = nx.DiGraph() def add_children(parent, children_): for data in children_: child = data[ident] 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 != ident and k != children } graph.add_node(child, **nodedata) root = data[ident] children_ = data.get(children, []) nodedata = {str(k): v for k, v in data.items() if k != ident and k != children} graph.add_node(root, **nodedata) add_children(root, children_) return graph