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# code from http://bbengfort.github.io/snippets/2016/06/23/graph-tool-from-networkx.html
import networkx as nx
import graph_tool as gt
def get_prop_type(value, key=None):
"""
Performs typing and value conversion for the graph_tool PropertyMap class.
If a key is provided, it also ensures the key is in a format that can be
used with the PropertyMap. Returns a tuple, (type name, value, key)
"""
# Deal with the value
if isinstance(value, bool):
tname = 'bool'
elif isinstance(value, int):
tname = 'float'
value = float(value)
elif isinstance(value, float):
tname = 'float'
elif isinstance(value, dict):
tname = 'object'
else:
tname = 'string'
value = str(value)
return tname, value, key
def nx2gt(nxG):
"""
Converts a networkx graph to a graph-tool graph.
"""
# Phase 0: Create a directed or undirected graph-tool Graph
gtG = gt.Graph(directed=nxG.is_directed())
# Add the Graph properties as "internal properties"
for key, value in nxG.graph.items():
# Convert the value and key into a type for graph-tool
tname, value, key = get_prop_type(value, key)
prop = gtG.new_graph_property(tname) # Create the PropertyMap
gtG.graph_properties[key] = prop # Set the PropertyMap
gtG.graph_properties[key] = value # Set the actual value
# Phase 1: Add the vertex and edge property maps
# Go through all nodes and edges and add seen properties
# Add the node properties first
nprops = set() # cache keys to only add properties once
for node, data in nxG.nodes(data=True):
# Go through all the properties if not seen and add them.
for key, val in data.items():
if key in nprops:
continue # Skip properties already added
# Convert the value and key into a type for graph-tool
tname, _, key = get_prop_type(val, key)
prop = gtG.new_vertex_property(tname) # Create the PropertyMap
gtG.vertex_properties[key] = prop # Set the PropertyMap
# Add the key to the already seen properties
nprops.add(key)
# Also add the node id: in NetworkX a node can be any hashable type, but
# in graph-tool node are defined as indices. So we capture any strings
# in a special PropertyMap called 'id' -- modify as needed!
gtG.vertex_properties['id'] = gtG.new_vertex_property('string')
# Add the edge properties second
eprops = set() # cache keys to only add properties once
for src, dst, data in nxG.edges(data=True):
# Go through all the edge properties if not seen and add them.
for key, val in data.items():
if key in eprops:
continue # Skip properties already added
# Convert the value and key into a type for graph-tool
tname, _, key = get_prop_type(val, key)
prop = gtG.new_edge_property(tname) # Create the PropertyMap
gtG.edge_properties[key] = prop # Set the PropertyMap
# Add the key to the already seen properties
eprops.add(key)
# Phase 2: Actually add all the nodes and vertices with their properties
# Add the nodes
vertices = {} # vertex mapping for tracking edges later
for node, data in nxG.nodes(data=True):
# Create the vertex and annotate for our edges later
v = gtG.add_vertex()
vertices[node] = v
# Set the vertex properties, not forgetting the id property
data['id'] = str(node)
for key, value in data.items():
gtG.vp[key][v] = value # vp is short for vertex_properties
# Add the edges
for src, dst, data in nxG.edges(data=True):
# Look up the vertex structs from our vertices mapping and add edge.
e = gtG.add_edge(vertices[src], vertices[dst])
# Add the edge properties
for key, value in data.items():
gtG.ep[key][e] = value # ep is short for edge_properties
# Done, finally!
return gtG