Reference library

Python Code Samples

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

4 matches
Data pipelines & processing medium

How to Implement Slowly Changing Dimension Type 2 History in Python

Build a type-2 slowly changing dimension pipeline that closes old records and opens new ones when customer data changes.

scd dimension history
Python
from datetime import datetime, timedelta

def apply_scd_type2(records, current_date):
    """Returns active records after inserting new records with type-2 history."""
    history = []
    active = {}

    for record in records:
        key = record["customer_id"]
        if key in active:
            active[key]["end…
13 0 Open
System design patterns medium

Circuit Breaker Pattern in Python: Closed, Open, and Half-Open States

Implement a circuit breaker with closed, open, and half-open states to prevent repeated calls to failing services and allow recovery after a timeout.

circuit-breaker resilience fault-tolerance
Python
class CircuitBreaker:
    def __init__(self, failure_threshold=3, timeout_seconds=5):
        self.failure_threshold = failure_threshold
        self.timeout_seconds = timeout_seconds
        self.state = "closed"
        self.failure_count = 0
        self.last_failure_time = None

    def record_success(self):
     …
14 0 Open
Reliability & rate limiting medium

How to Implement a Circuit Breaker in Python

A Python dataclass that provides circuit breaker logic with closed, open, and half-open states to fail fast on repeated errors.

circuit-breaker resilience fault-tolerance
Python
from dataclasses import dataclass
from datetime import datetime, timedelta
import time


@dataclass
class CircuitBreaker:
    failure_threshold: int = 3
    timeout_seconds: float = 5.0
    failures: int = 0
    state: str = "closed"
    last_failure: datetime = None

    def call(self, func):
        if self.state ==…
15 0 Open
Production deployment patterns medium

How to Drain a Connection Pool Before Exit in Python

Gracefully close all pooled sockets using a thread-safe ConnectionPool that drains connections before program exit.

connection-pool sockets threading
Python
import socket
import threading
import time
import random

class ConnectionPool:
    def __init__(self, size=5):
        self.pool = []
        self.lock = threading.Lock()
        self.closed = False
        for _ in range(size):
            self.pool.append(self.create_connection())
    
    def create_connection(sel…
13 0 Open

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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.