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System design patterns

Sharding, load balancing, CAP tradeoffs, and scaling patterns — interview and production ready.

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How to Implement a Data Helper Class in Python

Build a beginner-friendly DataHelper class using dataclasses and key system design patterns like Command, Strategy, and Map.

dataclass data-helper design-patterns

Python

from __future__ import annotations
from dataclasses import dataclass, field
from typing import Any, Dict, List, Optional


@dataclass
class DataHelper:
    """A beginner-friendly data utility with common system design patterns."""
    data: List[Dict[str, Any]] = field(default_factory=list)

    def add_record(self, r…

13 0 Open

System design patterns easy

How to Implement the Prototype Pattern with Deep Copy in Python

Implements the Prototype design pattern using copy.deepcopy to clone complex objects without sharing mutable state.

prototype-pattern deepcopy dataclasses

Python

import copy
from dataclasses import dataclass, field
from typing import List

@dataclass
class Engine:
    horsepower: int

@dataclass
class Car:
    brand: str
    engine: Engine
    accessories: List[str] = field(default_factory=list)

def clone_prototype(car: Car) -> Car:
    return copy.deepcopy(car)

if __name__ …

13 0 Open

System design patterns easy

Observer Pattern with Mock Metrics in Python

Implement the Observer pattern with a mock metrics collector to track state changes and verify notifications.

observer mock design pattern

Python

import unittest
from unittest.mock import Mock


class Subject:
    def __init__(self):
        self._state = 0
        self._observers = []

    def attach(self, observer):
        self._observers.append(observer)

    def set_state(self, value):
        if value != self._state:
            self._state = value
      …

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