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Python Code Samples

Easy snippets you can copy, study, and run in the browser editor.

3 matches
System design patterns easy

Round Robin Load Balancer in Python

This code simulates round robin load balancing by distributing a list of requests evenly across a list of servers.

load-balancing round-robin system-design
Python
def round_robin_servers(requests: list[str], servers: list[str]) -> dict[str, list[str]]:
    assignments = {server: [] for server in servers}
    for idx, request in enumerate(requests):
        server = servers[idx % len(servers)]
        assignments[server].append(request)
    return assignments


if __name__ == "_…
13 0 Open
Streaming & messaging easy

Mock NATS queue group load balancing in Python

Simulates a NATS queue group where each message is delivered to exactly one subscriber using random selection with a lightweight mock.

nats queue-group messaging
Python
import random
import time
from collections import defaultdict


class MockQueueGroup:
    """Mock a NATS queue group: each message is delivered to exactly one subscriber."""

    def __init__(self, subscribers):
        self.subscribers = subscribers

    def publish(self, message):
        receiver = random.choice(se…
13 0 Open
Database scaling & optimization easy

Route SELECT Queries to Read Replicas in Python

A mock round-robin router that forwards SELECT queries to read replicas and sends writes to the primary.

database replication routing
Python
import random

class ReadReplicaRouter:
    """Round-robin router that sends SELECT queries to read replicas."""
    
    def __init__(self, replicas):
        self.replicas = replicas
        self.counter = 0
    
    def route(self, sql):
        if sql.strip().upper().startswith("SELECT"):
            replica = sel…
13 0 Open

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Guide: free Python code samples library

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PythonSkillset code samples are short, focused examples organised by topic and difficulty. Every snippet is server-rendered HTML — readable by search engines and easy to copy. Open any sample, read the notes, copy the code, then press Try in editor to run it in the browser with Pyodide.

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  2. Open a sample, read How it works, and copy the code block
  3. Run it in the IDE, tweak values, then take a related quiz or tutorial lesson

Samples vs tutorials and challenges

Samples are quick reference — one concept per page. For step-by-step teaching, use our Python tutorials. To test yourself, try quizzes or coding challenges. Clean up style with the Python formatter.