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Python Code Samples

Copy-ready Python snippets by topic and difficulty — short, focused, and runnable in the browser editor.

7 matches
Lists & loops easy

Round Robin Merge Multiple Lists in Python

Merge multiple lists by taking one element from each in turn, stopping when all lists are exhausted.

lists merge interleave
Python
from itertools import cycle

def round_robin_merge(*lists):
    """Merge multiple lists by taking one element from each in turn."""
    result = []
    max_len = max(len(lst) for lst in lists)
    
    for i in range(max_len):
        for lst in lists:
            if i < len(lst):
                result.append(lst[i])…
14 0 Open
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 medium

Mock Kafka Consumer Group Partition Assignment in Python

Simulates a Kafka consumer group's round-robin partition assignment with a Python class and prints assignments per consumer.

kafka consumer-group partition-assignment
Python
from collections import defaultdict


class ConsumerGroupAssignment:
    def __init__(self, group_name, topics_partitions):
        self.group_name = group_name
        self.consumers = {}
        self.assignments = defaultdict(set)
        topics_partitions = sorted(
            [(topic, partition) for topic, partiti…
14 0 Open
Microservices patterns easy

How to Mock a Server-Side Load Balancer in Python

A simple Python class that mimics a server-side load balancer with round-robin, random, and least-connections selection strategies.

load-balancer microservices simulation
Python
import itertools
import random

class LoadBalancer:
    def __init__(self, servers=None):
        self.servers = servers if servers else ["server1", "server2", "server3"]
        self.counter = itertools.count(1)

    def round_robin(self):
        return next(self.counter) % len(self.servers)

    def random_selectio…
13 0 Open
Microservices patterns easy

How to implement round-robin load balancing in Python

Implement a client-side round-robin load balancer that distributes requests sequentially across a list of mock servers using itertools.cycle.

load balancing round robin microservices
Python
import itertools
import random


class MockServer:
    def __init__(self, name):
        self.name = name

    def handle_request(self, request_id):
        return f"Server {self.name} handled request #{request_id}"


class RoundRobinLoadBalancer:
    def __init__(self, servers):
        self.servers = servers
       …
14 0 Open
Database scaling & optimization easy

Rebalance Shard Ranges Across Nodes in Python

A mock rebalancing function that shuffles shard ranges and distributes them evenly across nodes using round-robin assignment.

sharding rebalancing dataclass
Python
import random
from dataclasses import dataclass

@dataclass
class Shard:
    id: int
    start: int
    end: int

def rebalance_shards(shards: list[Shard], node_count: int) -> dict[int, list[Shard]]:
    """Mock rebalancing of shard ranges across nodes."""
    all_ranges = [(s.start, s.end) for s in shards]
    random…
11 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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  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

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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.