def add_node(self, n, **attr):
"""Add a single node n.
If n is not a string, conversion to a string will be attempted.
String conversion will work if n has valid string representation
(try str(n) if you are unsure).
>>> G=AGraph()
>>> G.add_node('a')
>>> G.nodes()
['a']
>>> G.add_node(1) # will be converted to a string
>>> G.nodes()
['a', '1']
Attributes can be added to nodes on creation
(attribute values must be strings)
>>> G.add_node(2,color='red')
See http://www.graphviz.org/doc/info/attrs.html
for a list of attributes.
Anonymous Graphviz nodes are currently not implemented.
"""
if not self._is_string_like(n): n=str(n)
n=n.encode(self.charset)
try:
nh=gv.agnode(self.handle,n,_Action.find)
except KeyError:
nh=gv.agnode(self.handle,n,_Action.create)
node=Node(self,nh=nh)
node.attr.update(**attr)
def __new__(self,graph,name=None,nh=None):
if nh is not None:
n=str.__new__(self,gv.agnameof(nh))
else:
n=str.__new__(self,name)
try:
nh=gv.agnode(graph.handle,n,_Action.find)
except KeyError:
raise KeyError("Node %s not in graph."%n)
n.ghandle=graph.handle
n.attr=ItemAttribute(nh,1)
n.handle=nh
return n
def remove_node(self,n):
"""Remove the single node n.
Attempting to remove a node that isn't in the graph will produce
an error.
>>> G=AGraph()
>>> G.add_node('a')
>>> G.remove_node('a')
"""
if not self._is_string_like(n): n=str(n)
try:
nh=gv.agnode(self.handle,n,_Action.find)
gv.agdelnode(self.handle,nh)
except KeyError:
raise KeyError("Node %s not in graph."%n)
def get_handle(self):
"""Return pointer to graphviz node object."""
return gv.agnode(self.ghandle,self,_Action.find)
