How do I implement Huffman coding in Python?

How do I implement Huffman coding in Python?

To implement Huffman coding in Python, you'll need to create a frequency table, build a priority queue, and then generate the codes.

Can you show me a sample code for that?

Sure! Here's a simple implementation:

import heapq
from collections import defaultdict

class Node:
    def __init__(self, char, freq):
        self.char = char
        self.freq = freq
        self.left = None
        self.right = None

    def __lt__(self, other):
        return self.freq < other.freq

def build_huffman_tree(text):
    frequency = defaultdict(int)
    for char in text:
        frequency[char] += 1

    priority_queue = [Node(char, freq) for char, freq in frequency.items()]
    heapq.heapify(priority_queue)

    while len(priority_queue) > 1:
        left = heapq.heappop(priority_queue)
        right = heapq.heappop(priority_queue)
        merged = Node(None, left.freq + right.freq)
        merged.left = left
        merged.right = right
        heapq.heappush(priority_queue, merged)

    return priority_queue[0]

def generate_codes(node, prefix='', codebook={}):
    if node:
        if node.char is not None:
            codebook[node.char] = prefix
        generate_codes(node.left, prefix + '0', codebook)
        generate_codes(node.right, prefix + '1', codebook)
    return codebook

text = "example text"
huffman_tree = build_huffman_tree(text)
codes = generate_codes(huffman_tree)
print(codes)

What does this code do?

This code builds a Huffman tree from the input text and generates a dictionary of Huffman codes for each character.