How Do I Print a Trie Data Structure in Python?


Heather Bennett

Printing a Trie data structure in Python can be a useful task when you want to visualize the structure of the trie and its contents. The Trie data structure, also known as a prefix tree, is commonly used for efficient string search and storage operations.

What is a Trie?

A Trie is a tree-like data structure that stores strings efficiently. It is particularly useful for searching for words or prefixes in large collections of words. Each node in the Trie represents a character, and the edges between nodes represent the characters that can follow the current character.

Implementing a Trie in Python

To print a Trie data structure in Python, we first need to implement the Trie itself. Here’s an example implementation:

class Node:
    def __init__(self):
        self.children = {}
        self.is_end_of_word = False

class Trie:
    def __init__(self):
        self.root = Node()

    def insert(self, word):
        node = self.root
        for char in word:
            if char not in node.children:
                node.children[char] = Node()
            node = node.children[char]
        node.is_end_of_word = True

    def search(self, word):
        node = self.children:
                return False
            node = node.children[char]
        return node.is_end_of_word

Printing a Trie

To print the entire trie, we can use depth-first search (DFS) traversal. Here’s how we can modify our Trie class to include a print method:

class Node:
    # .. existing code .

class Trie:
    # .

    def print_trie(self):
        self._print_trie_helper(self.root, "")

    def _print_trie_helper(self, node, prefix):
        if node.is_end_of_word:
        for char, child in node.children.items():
            self._print_trie_helper(child, prefix + char)

Example Usage

Let’s see how we can use our Trie and print the data structure:

trie = Trie()
words = ["apple", "banana", "application", "book", "ball"]
for word in words:


The above code will output:

  • apple
  • application
  • banana
  • ball
  • book

This is the visual representation of the Trie data structure with the inserted words. Each word is printed on a separate line. The underlined text represents the end of a word.


You have successfully learned how to print a Trie data structure in Python. By using a combination of depth-first search traversal and proper implementation of the Trie class, you can visualize the structure and contents of a Trie. This can be particularly useful for debugging or understanding how your Trie is organized.

Remember to experiment with different words and test cases to further enhance your understanding of Tries.

Note: In real-world scenarios, Tries are often used in combination with other data structures or algorithms to solve more complex problems efficiently.

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