binarytree Documentation

Binarytree supports level-order indexing, allowing you to access, replace, or delete nodes using their position in a breadth-first traversal. This is similar to how binary heaps are represented in arrays.

• Access: Use root[index] to get the node at that index.
• Replace: Use root[index] = new_node to replace a subtree.
• Delete: Use del root[index] to remove a subtree.
• Visualization: Use root.pprint(index=True) to print the tree with both node values and their level-order indices.

from binarytree import Node

root = Node(1)
root.left = Node(2)
root.right = Node(3)
root.left.right = Node(4)
root.left.right.left = Node(5)

# View indices
root.pprint(index=True)

# Access node at index 9
node_9 = root[9]

# Replace node at index 4
root[4] = Node(6, left=Node(7), right=Node(8))

# Delete node at index 1
del root[1]

You can install the binarytree library using pip or conda.

Using pip:

pip install binarytree --upgrade

Using conda:

conda install binarytree -c conda-forge

To use the tree rendering features in binarytree (version 6.0.0+), you must install the Graphviz software on your operating system and ensure the Graphviz executables are in your system PATH.

# Ubuntu and Debian
sudo apt install graphviz

# Fedora and CentOS
sudo yum install graphviz

# Windows using choco (or winget)
choco install graphviz

You can convert a tree to a list representation (where all null nodes in each level are present) or a more compact representation (often used in LeetCode).

• root.values: Returns the standard list representation.
• root.values2: Returns the compact list representation.
• build(list): Builds a tree from the standard list representation.
• build2(list): Builds a tree from the compact list representation.

You can use the Node.graphviz() method to generate a graphviz.Digraph object from a binary tree. This object can be used to inspect the DOT (graph description language) body or to render the tree as an image. Any arguments passed to graphviz() are passed directly into the Digraph.__init__ constructor.

from binarytree import tree

t = tree()

# Generate a graphviz.Digraph object
# Arguments to this method are passed into Digraph.__init__
graph = t.graphviz()

# Get DOT (graph description language) body
print(graph.body)

# Render the binary tree
graph.render()

The Node class provides properties that return lists of nodes following standard traversal orders:

• inorder
• preorder
• postorder
• levelorder (also accessible via list(root))

from binarytree import Node

root = Node(1)
root.left = Node(2)
root.right = Node(3)
root.left.left = Node(4)
root.left.right = Node(5)

print(root.inorder)    # [Node(4), Node(2), Node(5), Node(1), Node(3)]
print(root.preorder)  # [Node(1), Node(2), Node(4), Node(5), Node(3)]
print(root.postorder) # [Node(4), Node(5), Node(2), Node(3), Node(1)]
print(root.levelorder)# [Node(1), Node(2), Node(3), Node(4), Node(5)]
print(list(root))     # [Node(1), Node(2), Node(3), Node(4), Node(5)]