from .abstractiter import AbstractIter
[docs]class LevelOrderGroupIter(AbstractIter):
"""
Iterate over tree applying level-order strategy with grouping starting at `node`.
Return a tuple of nodes for each level. The first tuple contains the
nodes at level 0 (always `node`). The second tuple contains the nodes at level 1
(children of `node`). The next level contains the children of the children, and so on.
>>> from anytree import Node, RenderTree, AsciiStyle, LevelOrderGroupIter
>>> f = Node("f")
>>> b = Node("b", parent=f)
>>> a = Node("a", parent=b)
>>> d = Node("d", parent=b)
>>> c = Node("c", parent=d)
>>> e = Node("e", parent=d)
>>> g = Node("g", parent=f)
>>> i = Node("i", parent=g)
>>> h = Node("h", parent=i)
>>> print(RenderTree(f, style=AsciiStyle()).by_attr())
f
|-- b
| |-- a
| +-- d
| |-- c
| +-- e
+-- g
+-- i
+-- h
>>> [[node.name for node in children] for children in LevelOrderGroupIter(f)]
[['f'], ['b', 'g'], ['a', 'd', 'i'], ['c', 'e', 'h']]
>>> [[node.name for node in children] for children in LevelOrderGroupIter(f, maxlevel=3)]
[['f'], ['b', 'g'], ['a', 'd', 'i']]
>>> [[node.name for node in children]
... for children in LevelOrderGroupIter(f, filter_=lambda n: n.name not in ('e', 'g'))]
[['f'], ['b'], ['a', 'd', 'i'], ['c', 'h']]
>>> [[node.name for node in children]
... for children in LevelOrderGroupIter(f, stop=lambda n: n.name == 'd')]
[['f'], ['b', 'g'], ['a', 'i'], ['h']]
"""
@staticmethod
def _iter(children, filter_, stop, maxlevel):
level = 1
while children:
yield tuple([child for child in children if filter_(child)])
level += 1
if AbstractIter._abort_at_level(level, maxlevel):
break
children = LevelOrderGroupIter._get_grandchildren(children, stop)
@staticmethod
def _get_grandchildren(children, stop):
next_children = []
for child in children:
next_children = next_children + AbstractIter._get_children(child.children, stop)
return next_children