Implement Tree Data Structure In Python

Implement a tree data structure in Python. The following code shows how to implement a tree in the Python programming language. 

Code:

class Node:
    def __init__(self, data):
        self.data = data
        self.parent = None
        self.left = None
        self.right = None

    def __repr__(self):
        return repr(self.data)

    def add_left(self, node):
        self.left = node
        if node is not None:
            node.parent = self

    def add_right(self, node):
        self.right = node
        if node is not None:
            node.parent = self


class Tree:

    def __init__(self):
        self.root = None

    def make_tree(self):
        node_one = Node(1)
        node_two = Node(2)
        node_three = Node(3)
        node_four = Node(4)
        node_five = Node(5)
        node_six = Node(6)
        node_seven = Node(7)
        node_eight = Node(8)
        node_nine = Node(9)
        node_ten = Node(10)

        self.root = node_two

        node_two.add_left(node_seven)
        node_two.add_right(node_nine)

        node_seven.add_left(node_one)
        node_seven.add_right(node_six)

        node_six.add_left(node_five)
        node_six.add_right(node_ten)

        node_nine.add_right(node_eight)

        node_eight.add_left(node_three)
        node_eight.add_right(node_four)

    def pre_order(self, node):
        print(node, end=' ')
        if node.left:
            self.pre_order(node.left)
        if node.right:
            self.pre_order(node.right)

    def post_order(self, node):
        if node.left:
            self.post_order(node.left)
        if node.right:
            self.post_order(node.right)
        print(node, end=' ')

    def in_order(self, node):
        if node.left:
            self.in_order(node.left)
        print(node, end=' ')
        if node.right:
            self.in_order(node.right)


if __name__ == '__main__':
    tree = Tree()
    tree.make_tree()

    print('Pre order')
    tree.pre_order(tree.root)

    print('\nPost order')
    tree.post_order(tree.root)

    print('\nIn order')
    tree.in_order(tree.root)
    print('\nDone')

 

Output:

Pre order
2 7 1 6 5 10 9 8 3 4 
Post order
1 5 10 6 7 3 4 8 9 2 
In order
1 7 5 6 10 2 9 3 8 4 
Done