Python Code
Samples
Medium snippets you can copy, study, and run in the browser editor.
How to Build an Anti-Corruption Layer in Python
Wrap a legacy system with a translation layer that converts awkward legacy data into a clean, modern DTO (Data Transfer Object) for use by new code.
class LegacyOrderSystem:
"""Legacy system with awkward, unstructured data."""
def get_order(self):
return {
"order_id": "ORD-123",
"cust": "Acme Corp",
"items": [{"sku": "A1", "qty": 2, "price_each": 10.0}],
"ship_to": "123 Main St, Springfield"
}…How to Migrate a Legacy Facade with the Strangler Fig Pattern in Python
Use a facade to wrap a legacy API and incrementally migrate callers to a modern interface, following the strangler fig pattern.
class LegacyAPI:
"""Simulates the legacy system's raw interface."""
def get_user(self, user_id):
return {"id": user_id, "name": "Alice", "legacy": True}
class UserService:
"""Facade that wraps the legacy system with a modern interface."""
def __init__(self, legacy_api=None):
self.lega…How to Expand a Contract and Migrate Data in Python
Expand an old data contract by renaming fields and adding defaults, then migrate to a final version with deepcopy isolation.
import json
from copy import deepcopy
# Mock data representing a user record (old contract)
old_contract = {
"id": 1,
"name": "Alice",
"email": "alice@example.com",
"age": 30,
"status": "active"
}
# Expanded contract: adds fields with defaults and renames some fields
expand_rules = {
"id": "u…Zero Downtime Migration with Dual Write Pattern in Python
Implement a dual-write pattern that writes user data to both legacy and new systems simultaneously to enable zero-downtime migration.
from datetime import datetime
import json
class UserService:
def __init__(self):
self.legacy_db = {}
self.new_db = {}
self.migration_log = []
def write_user(self, user_id, name, email):
# Write to new system first
user_record = {
"id": user_id,
…Browse by section
Each section groups closely related Python snippets.
Guide: free Python code samples library
Copy-ready Python snippets for learners and developers
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.
How to use this library
- Pick a topic section — strings, lists, files, functions, and more
- Open a sample, read How it works, and copy the code block
- 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.