def clear(self):
"""Remove all nodes, edges, and attributes from the graph."""
self.edge_attr.clear()
self.node_attr.clear()
self.graph_attr.clear()
# now "close" existing graph and create a new graph
name=gv.agnameof(self.handle)
strict=self.strict
directed=self.directed
gv.agclose(self.handle)
self.handle=gv.agraphnew(name,strict,directed)
def __init__(self, thing=None, file=None, name=None,
data=None, string=None, strict=True, directed=False,
handle=None,**attr):
# atttempt to guess input type
if isinstance(thing,dict):
data=thing # a dictionary of dictionaries (or lists)
if hasattr(thing,'own'): # a Swig pointer - graph handle
handle=thing
if self._is_string_like(thing):
if (thing.startswith("strict") or
thing.startswith("digraph") or
thing.startswith("graph")):
string=thing # this is a dot format graph in a string
else:
file=thing # assume this is a file name
self.charset='UTF-8' # default charset encoding
# input type guessed or specified - now init graph
if handle is None: # the graph pointer (handle)
try:
self.handle=gv.agraphnew(name,strict,directed) # new graph
except TypeError:
raise TypeError("Graph name must be a string: %s"%name)
else:
self.handle=handle # use pointer to exisiting graph
# read from filename
if file is not None:
self.read(file)
# load from dict of dicts or dict of lists
if data is not None:
for node in data:
for nbr in data[node]:
self.add_edge(node,nbr)
self.add_nodes_from(data.keys())
# load from string
if string is not None:
self.from_string(string)
# assign any attributes specified through keywords
self.graph_attr=Attribute(self.handle,0) # default graph attributes
self.graph_attr.update(attr) # apply attributes passed to init
self.node_attr=Attribute(self.handle,1) # default node attributes
self.edge_attr=Attribute(self.handle,2) # default edge attribtes
