Reference library

Python Code Samples

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

30 matches
A/B testing & experimentation medium

Check Sample Ratio Mismatch in Python

Estimates the probability that a simple random sample's proportion differs from the population proportion by more than 10% using simulation.

simulation statistics ab-testing
Python
import random


def sample_ratio_mismatch(population_size: int, sample_size: int, p: float) -> float:
    """
    Estimate the probability that a simple random sample's proportion
    differs from the population proportion by more than 10%.
    """
    total_counts = [0, 0]
    for _ in range(10000):
        sample = …
15 0 Open
Database scaling & optimization medium

Composite index leftmost prefix in Python

Simulate a composite index in SQLite and check whether query columns match the leftmost prefix rule for index usage.

sqlite indexes database
Python
import sqlite3


def get_indexed_columns(table_name):
    """Simulate a composite index by reading column names that start with 'idx_'."""
    conn = sqlite3.connect(":memory:")
    conn.execute(f"CREATE TABLE {table_name} (id INTEGER, idx_col1 TEXT, idx_col2 INTEGER, other TEXT)")
    conn.execute(f"CREATE INDEX idx_…
14 0 Open
Database scaling & optimization medium

How to Simulate Colocated Shard Joins in Python

Groups shards by their node and merges co-located shards into a single logical unit, checking capacity constraints.

sharding database distributed-systems
Python
import random
from collections import defaultdict


def simulate_colocated_shards_join(nodes: list[dict], shards: list[dict]) -> dict:
    """
    Simulates the join of co-located shards (on the same node) into a single
    logical shard. Returns the resulting node-to-shard mapping.

    Each node: {'id': str, 'capaci…
11 0 Open
Auth & security at scale medium

How to Sign and Verify with Ed25519 in Python

A minimal Ed25519 sign-and-verify helper that generates a key pair, signs a message, and checks the signature with the cryptography library.

ed25519 cryptography signing
Python
import hashlib
from cryptography.hazmat.primitives.asymmetric import ed25519
from cryptography.hazmat.primitives import serialization

def sign_verify_mock(
    message: bytes,
    private_key: ed25519.Ed25519PrivateKey,
    public_key: ed25519.Ed25519PublicKey
) -> tuple[bool, bytes]:
    signature = private_key.sign…
13 0 Open
Production deployment patterns medium

How to Simulate Blue-Green Deployment Switch in Python

A mock Blue-Green deployment class that deploys new versions to an inactive environment, runs a health check, switches traffic, and supports rollback in Python.

deployment blue-green mock
Python
import random
import time

class BlueGreenDeployment:
    def __init__(self, initial_env="blue"):
        self.environments = {"blue": "v1.0", "green": "v1.0"}
        self.active_env = initial_env
        self.running = True

    def deploy_new_version(self, version, target_env):
        if target_env == self.active_…
16 0 Open
Production deployment patterns medium

How to Smoke Test a Deployment in Python with unittest.mock

Run a post-deploy smoke test by mocking the deployment status check to verify your health-check logic returns PASS/FAIL.

deployment smoke-test unittest-mock
Python
import unittest
from unittest.mock import Mock, patch

class DeploymentService:
    def check_status(self):
        return "unknown"

def smoke_test_deploy():
    service = DeploymentService()
    with patch.object(service, "check_status", return_value="healthy") as mock_check:
        status = service.check_status()
…
13 0 Open

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