def remove_subtree(self, nid):
"""
Return a subtree deleted from this tree. If nid is None, an
empty tree is returned.
For the original tree, this method is similar to
`remove_node(self,nid)`, because given node and its children
are removed from the original tree in both methods.
For the returned value and performance, these two methods are
different:
`remove_node` returns the number of deleted nodes;
`remove_subtree` returns a subtree of deleted nodes;
You are always suggested to use `remove_node` if your only to
delete nodes from a tree, as the other one need memory
allocation to store the new tree.
"""
st = Tree()
if nid is None:
return st
if not self.contains(nid):
raise NodeIDAbsentError("Node '%s' is not in the tree" % nid)
st.root = nid
parent = self[nid].bpointer
self[nid].bpointer = None # reset root parent for the new tree
removed = []
for id in self.expand_tree(nid):
removed.append(id)
for id in removed:
st._nodes.update({id: self._nodes.pop(id)})
# Update its parent info
self.__update_fpointer(parent, nid, Node.DELETE)
return st
def remove_subtree(self, nid):
"""
Return a subtree deleted from this tree. If nid is None, an
empty tree is returned.
For the original tree, this method is similar to
`remove_node(self,nid)`, because given node and its children
are removed from the original tree in both methods.
For the returned value and performance, these two methods are
different:
`remove_node` returns the number of deleted nodes;
`remove_subtree` returns a subtree of deleted nodes;
You are always suggested to use `remove_node` if your only to
delete nodes from a tree, as the other one need memory
allocation to store the new tree.
"""
st = Tree()
if nid is None:
return st
if not self.contains(nid):
raise NodeIDAbsentError("Node '%s' is not in the tree" % nid)
st.root = nid
parent = self[nid].bpointer
self[nid].bpointer = None # reset root parent for the new tree
removed = []
for id in self.expand_tree(nid):
removed.append(id)
for id in removed:
st._nodes.update({id: self._nodes.pop(id)})
# Update its parent info
self.__update_fpointer(parent, nid, Node.DELETE)
return st
def subtree(self, nid):
"""
Return a shallow COPY of subtree with nid being the new root.
If nid is None, return an empty tree.
If you are looking for a deepcopy, please create a new tree
with this shallow copy,
e.g.
new_tree = Tree(t.subtree(t.root), deep=True)
This line creates a deep copy of the entire tree.
"""
st = Tree()
if nid is None:
return st
if not self.contains(nid):
raise NodeIDAbsentError("Node '%s' is not in the tree" % nid)
st.root = nid
for node_n in self.expand_tree(nid):
st._nodes.update({self[node_n].identifier: self[node_n]})
return st
def subtree(self, nid):
"""
Return a shallow COPY of subtree with nid being the new root.
If nid is None, return an empty tree.
If you are looking for a deepcopy, please create a new tree
with this shallow copy,
e.g.
new_tree = Tree(t.subtree(t.root), deep=True)
This line creates a deep copy of the entire tree.
"""
st = Tree()
if nid is None:
return st
if not self.contains(nid):
raise NodeIDAbsentError("Node '%s' is not in the tree" % nid)
st.root = nid
for node_n in self.expand_tree(nid):
st._nodes.update({self[node_n].identifier: self[node_n]})
return st
