python 迭代器

class Node:
 def __init__(self, value):
    self._value = value
    self._children = []
 def  __repr__(self):
     return 'Node({!r})'.format(self._value)
 def add_child(self, node):
  self._children.append(node)
# Example
if __name__ == '__main__':
  root = Node(0)
  # print root
  # print type(root)
  child1 = Node(1)
  child2 = Node(2)
  root.add_child(child1)
  root.add_child(child2)
  for x in root._children:
      print x

C:Python27python.exe C:/Users/TLCB/PycharmProjects/untitled/mycompany/Django/a31.py
Node(1)
Node(2)

Process finished with exit code 0



class Node:
 def __init__(self, value):
    self._value = value
    self._children = []
 def  __repr__(self):
     return 'Node({!r})'.format(self._value)
 def add_child(self, node):
  self._children.append(node)
 def __iter__(self):
   return iter(self._children)
# Example
if __name__ == '__main__':
  root = Node(0)
  # print root
  # print type(root)
  child1 = Node(1)
  child2 = Node(2)
  root.add_child(child1)
  root.add_child(child2)
  # Outputs Node(1), Node(2)
  for ch in root:
      print(ch)


C:Python27python.exe C:/Users/TLCB/PycharmProjects/untitled/mycompany/Django/a31.py
Node(1)
Node(2)

Process finished with exit code 0