binary tree

water0x

class BinaryTree:
    def __init__(self, root):
        self.key = root
        self.left = None
        self.right = None

    def tree_walk(self):
        if self.get_root() != None:
            self.left.tree_walk()
            print self.get_root(), " "
            self.left.tree_walk()

    def insert_left(self, new_node):
        if self.left == None:
            self.left = BinaryTree(new_node)
        else:
            t = BinaryTree(new_node)
            t.left = self.left
            self.left = t

    def insert_right(self, new_node):
        if self.right == None:
            self.right = BinaryTree(new_node)
        else:
            t = BinaryTree(new_node)
            t.right = self.right
            self.right = t

    def get_left(self):
        return self.left

    def get_right(self):
        return self.right

    def set_root(self, obj):
        self.key = obj

    def get_root(self):
        return self.key


r = BinaryTree('a')
print "key of root is ", r.get_root()
print "left key of node is ", r.get_left()
r.insert_left('b')
print "now, left key of node is ", r.get_left()
print "what key of left root node is ", r.get_left().get_root()
r.insert_right('c')
print "right key of node is ", r.get_right()
print "what key of right root node is ", r.get_right().get_root()
r.get_right().set_root('hello')
print "has just inserted value is ", r.get_right().get_root()
r.tree_walk()


    self.left.tree_walk()

AttributeError: 'NoneType' object has no attribute 'tree_walk'

这里要怎么改才不是NoneType object遍历

murdercool

猜猜看，是这样？

1.     def tree_walk(self):
   
2.         if self.left != None:
   
3.             self.left.tree_walk()
   
4.             print self.get_root(), " "
   
5.             self.left.tree_walk()

复制代码

water0x

回复 2# murdercool


    def tree_walk(self):
           if self.get_root() != None:
                self.get_left().tree_walk()
                print self.get_root()
                self.get_right().tree_walk()

仍然不对

kyrie_liu

def tree_walk(self):
      # 这里其实啥都没啊。