Python

Decorators Functools

Deprecation Warning Decorator
Junior
Timing Log Decorator
Junior
Specialized Functions With functools.partial
Junior
Parametrized @retry Decorator
Mid
Retry Decorator With Exponential Backoff
Mid
@require_permission Access-Control Decorator
Mid
Function Timing And Logging Decorator
Mid
Type-Dispatched Serializer With singledispatch
Mid
Rate-Limiter Decorator
Senior
Runtime Type-Checking Decorator
Senior
Universal Timing Decorator
Senior
TTL Memoization Decorator
Senior
Memoize Decorator With LRU Eviction
Senior
Dual-Use Timing Utility
Senior
Precise Signatures With typing.overload
Senior
Type-Preserving Decorator With ParamSpec
Senior

Async Concurrency

Concurrent URL Fetching With gather
Mid
Run Blocking Code With run_in_executor
Mid
Yield Results With asyncio.as_completed
Mid
Async DB Connection Context Manager
Mid
Async Status Publisher To Queue
Mid
Producer-Consumer With Graceful Shutdown
Mid
Coordinate Workers With asyncio.Event
Mid
Producer-Consumer With asyncio.Queue
Senior
Async Timeout Wrapper With Cancellation
Senior
Async Size/Time Batch Flusher
Senior
Concurrency-Limited URL Fetcher
Senior
Async Task Queue With asyncio.Lock
Senior
Refactor Threaded I/O Script to asyncio
Senior
Race Coroutines and Cancel Losers
Senior
Async Requests-Per-Second Rate Limiter
Senior
Concurrent LLM Calls With asyncio
Senior
Structured Concurrency With asyncio.TaskGroup
Senior

Context Managers

Timing Context Manager
Junior
Generator Context Manager With @contextmanager
Junior
Transaction Context Manager
Mid
Temporary Directory Context Manager
Mid
Selective Exception-Suppressing Context Manager
Mid
Transactional List Context Manager
Mid
Class-Based Context Manager With Cleanup
Mid
Temporary State Override Context Manager
Mid
Open Many Files With ExitStack
Mid
Redirect stdout Context Manager
Mid
Atomic Write Context Manager
Senior

Iterators Generators

Custom Range Iterator Class
Junior
Fixed-Size Array With Dunder Methods
Junior
Infinite Cycling Iterator
Junior
ReverseRange Iterator Class
Junior
Lazy Log Error Filter Generator
Mid
Depth-First Nested Dict Iterator
Mid
Infinite Sequence Generator With take
Mid
Stream a Large File in Chunks
Mid
Buffered Batch Generator
Mid
Generator Pipeline: Filter, Transform, Aggregate
Mid
Float-Step range() Generator
Mid
Async Paginated API Generator
Mid
Memory-Efficient Tail Generator
Senior

Descriptors Metaclasses Attribute Control

Singleton via Custom Metaclass
Mid
PositiveInteger Validating Descriptor
Mid
Range-Validated Integer Descriptor
Mid
@synchronized Decorator With Lock
Mid
Type-Checked Attributes via __setattr__
Mid
Validated Attributes With Dunder Hooks
Mid
Type-Safe Attribute Descriptor
Mid
Metaclass Plugin Registry
Senior
Thread-Safe Singleton With Lock
Senior
Uppercasing Metaclass for String Attributes
Senior

Dunder Methods Data Models

Validated Temperature Property
Junior
Point NamedTuple With Computed Properties
Junior
DotDict via __getattr__/__setattr__
Mid
Optimize Instances With __slots__
Mid
Immutable Record With Frozen Fields
Mid
Recreate defaultdict via __missing__
Mid
Dataclass With Validation and Derived Fields
Mid
Frozen Ordered Dataclass Sorting
Mid
Make Instances Usable in Sets and Dicts
Mid
Version Class With total_ordering
Mid
Custom __copy__ and __deepcopy__ Semantics
Senior

Abstract Classes Protocols Generics

Structural Typing With typing.Protocol
Mid
Interface Validator With abc.ABCMeta
Senior
Generic Response[T] Wrapper
Senior
Generic Type-Safe Repository
Senior

Data Processing Transformation

Group Transactions With itertools.groupby
Junior
Top-K Frequent Words With Counter
Junior
Recursive Deep Merge of Dicts
Mid
Memory-Efficient CSV Aggregation Pipeline
Senior
Sessionize Event Logs by Inactivity
Senior

Typing Validation Pydantic

Refactor a Loop Using the Walrus Operator
Junior
Order State Enum and Transition Validator
Junior
Validate Nested JSON With TypedDict
Mid
Process Nested Data With match/case
Mid

Parsing Serialization Binary

Parse Log Lines With Named Groups
Junior
Nginx Log Top IPs By Status
Mid
Custom JSON Encoder for Complex Types
Mid
URL Shortener Core With Collision Handling
Mid
Pack and Unpack Binary Records With struct
Senior

Testing Mocking

Letter Grade From a Numeric Score
Junior
Mocking an External API Client
Mid
Monkeypatch Env Var and Function
Mid
Mock Retry With side_effect
Mid

Python Application Building Blocks

Exception Chaining With raise from
Junior
Argparse CLI With Subcommands
Junior
Recent Files By Glob With pathlib
Junior
Closure-Based Counter Factory
Junior
Callable Class With Call History
Mid
Parallelize CPU-Bound Work With Pool
Mid
Concurrent Tasks With ThreadPoolExecutor
Mid
Running-Average Coroutine With send()
Mid
Rotating File Logger With Custom Formatter
Mid
Stream Subprocess Output Line by Line
Mid
Request-Scoped Logging With contextvars
Senior
Read-Only Replica Routing Decorator
Senior
Weakref Auto-Evicting Object Cache
Senior

Python

Decorators Functools

Deprecation Warning Decorator

Timing Log Decorator

Specialized Functions With functools.partial

Parametrized @retry Decorator

Retry Decorator With Exponential Backoff

@require_permission Access-Control Decorator

Function Timing And Logging Decorator

Type-Dispatched Serializer With singledispatch

Rate-Limiter Decorator

Runtime Type-Checking Decorator

Universal Timing Decorator

TTL Memoization Decorator

Memoize Decorator With LRU Eviction

Dual-Use Timing Utility

Precise Signatures With typing.overload

Type-Preserving Decorator With ParamSpec

Async Concurrency

Concurrent URL Fetching With gather

Run Blocking Code With run_in_executor

Yield Results With asyncio.as_completed

Async DB Connection Context Manager

Async Status Publisher To Queue

Producer-Consumer With Graceful Shutdown

Coordinate Workers With asyncio.Event

Producer-Consumer With asyncio.Queue

Async Timeout Wrapper With Cancellation

Async Size/Time Batch Flusher

Concurrency-Limited URL Fetcher

Async Task Queue With asyncio.Lock

Refactor Threaded I/O Script to asyncio

Race Coroutines and Cancel Losers

Async Requests-Per-Second Rate Limiter

Concurrent LLM Calls With asyncio

Structured Concurrency With asyncio.TaskGroup

Context Managers

Timing Context Manager

Generator Context Manager With @contextmanager

Transaction Context Manager

Temporary Directory Context Manager

Selective Exception-Suppressing Context Manager

Transactional List Context Manager

Class-Based Context Manager With Cleanup

Temporary State Override Context Manager

Open Many Files With ExitStack

Redirect stdout Context Manager

Atomic Write Context Manager

Iterators Generators

Custom Range Iterator Class

Fixed-Size Array With Dunder Methods

Infinite Cycling Iterator

ReverseRange Iterator Class

Lazy Log Error Filter Generator

Depth-First Nested Dict Iterator

Infinite Sequence Generator With take

Stream a Large File in Chunks

Buffered Batch Generator

Generator Pipeline: Filter, Transform, Aggregate

Float-Step range() Generator

Async Paginated API Generator

Memory-Efficient Tail Generator

Descriptors Metaclasses Attribute Control

Singleton via Custom Metaclass

PositiveInteger Validating Descriptor

Range-Validated Integer Descriptor

@synchronized Decorator With Lock

Type-Checked Attributes via __setattr__

Validated Attributes With Dunder Hooks

Type-Safe Attribute Descriptor

Metaclass Plugin Registry

Thread-Safe Singleton With Lock

Uppercasing Metaclass for String Attributes

Dunder Methods Data Models

Validated Temperature Property

Point NamedTuple With Computed Properties

DotDict via __getattr__/__setattr__

Optimize Instances With __slots__

Immutable Record With Frozen Fields

Recreate defaultdict via __missing__

Type-Checked Attributes via setattr

DotDict via getattr/setattr

Optimize Instances With slots

Recreate defaultdict via missing

Custom copy and deepcopy Semantics