An example of a binary tree of python data structures

First, set up a binary tree node, there is a data data field, left, right two pointer fields

# -*- coding: utf - 8 - *-

                 
class TreeNode(object):

    def __init__(self, left=0, right=0, data=0):
        self.left = left
        self.right = right
        self.data = data

class BTree(object):

    def __init__(self, root=0):
        self.root = root

Manually build a binary tree

node1 = TreeNode(data=1)
node2 = TreeNode(node1, 0, 2)
node3 = TreeNode(data=3)
node4 = TreeNode(data=4)
node5 = TreeNode(node3, node4, 5)
node6 = TreeNode(node2, node5, 6)
node7 = TreeNode(node6, 0, 7)
node8 = TreeNode(data=8)
root = TreeNode(node7, node8, 'root')
bt = BTree(root)

And then you're going to have a binary tree down here

#  Generated binary tree 

# ------------------------
#          root
#       7        8
#     6
#   2   5
# 1    3 4
#
# -------------------------

In addition to manually specifying node nodes one by one, you can also create a create method that takes user input and adds binary tree nodes... Add with precontinuation, the code is as follows:

# -*- coding: utf - 8 - *-

           
class TreeNode(object):

    def __init__(self, left=0, right=0, data=0):
        self.left = left
        self.right = right
        self.data = data

           
class BTree(object):

    def __init__(self, root=0):
        self.root = root

    def is_empty(self):
        if self.root is 0:
            return True
        else:
            return False

    def create(self):
        temp = input('enter a value:')
        if temp is '#':
            return 0
        treenode = TreeNode(data=temp)
        if self.root is 0:
            self.root = treenode

        treenode.left = self.create()
        treenode.right = self.create()

Create a binary tree with create

# Run the file   Run under the interactive interpreter 

bt = BTree()

bt.create()
enter a value:9
enter a value:7
enter a value:6
enter a value:2
enter a value:1
enter a value:'#'
enter a value:'#'
enter a value:'#'
enter a value:5
enter a value:3
enter a value:'#'
enter a value:'#'
enter a value:4
enter a value:'#'
enter a value:'#'
enter a value:'#'
enter a value:8
enter a value:'#'
enter a value:'#'

You can get the same effect with create