What is Tree?

<aside> 💡 Tree is a non-linear data structure but hierarchy. The element that is on the top is known as root Tree because Tree is believed originally from root. The elements in the edge of Tree are called by leaf.

</aside>

Tree that is suitable to store the data that is not connected but is linear to each other but in a form of hierarchy.

In Python, a node is an essential building block used in various data structures. Let’s explore what nodes are and how they are implemented:

1. Node Basics:
   • A node is an individual part of a larger data structure.
   • It contains data and one or more links to other nodes.
   • Nodes can be used to represent tree structures or linked lists.
   • When nodes are used, it becomes possible to traverse from one node to another.
   • Nodes that have no links pointing to them except for the head node are considered “orphaned”.
   • Data structures containing nodes typically store two pieces of information in a node: the data value and a link to the next node.
   • A NULL value in the link part of a node’s info denotes that the path or data structure contains no further nodes.
2. Python Node Implementation:
   • In Python, a Node class can be created to represent nodes.
   • The Node class should have the following methods:
     • __init__(self, value, next_node=None): Initializes a node with a given value and an optional link to the next node.
     • set_next_node(self, next_node): Sets the link to the next node.
     • get_next_node(self): Returns the next node.
     • get_value(self): Returns the value stored in the node.

Here’s an example implementation of a Node class in Python:

class Node:
    def __init__(self, value, next_node=None):
        self.value = value
        self.next_node = next_node

    def set_next_node(self, next_node):
        self.next_node = next_node

    def get_next_node(self):
        return self.next_node

    def get_value(self):
        return self.value

Feel free to use this Node class to create linked lists or other data structures in your Python programs! 🌟

For more details and examples, you can refer to the Codecademy Cheatsheet on Nodes1.

Implementation

# Tree
class node:
  def __init__(self, ele):
    self.ele = ele
    self.left = None
    self.right = None

def preorder(self):
    if self:
      print(self.ele)
      preorder(self.left)
      preorder(self.right)
  
n = node('first')
n.left = node('second')
n.right = node('third')
preorder(n)

first
second
third

• first is root.
• first has 2 branches left and right.