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python

Python

# 🐍 Python — Complete Topics Reference

Start se end tak — ekdum kuch nahi chhodha. Ye hai tera Python ka Poora Brahmand.

# 📦 SECTION 1 — Python Fundamentals

# 1.1 Introduction

  • What is Python?
  • History (Guido van Rossum, 1991)
  • Python 2 vs Python 3 (always use 3.x)
  • CPython, PyPy, Jython, IronPython (interpreters)
  • How Python runs (Interpreter, Bytecode, .pyc)
  • REPL (Interactive Shell)
  • Installing Python & pip
  • Virtual Environments (venv, virtualenv, conda)
  • Running scripts: python script.py
  • __name__ == "__main__" idiom
  • PEP 8 — Style Guide (must follow!)
  • PEP 20 — The Zen of Python (import this)

# 1.2 Variables & Data Types

  • Variables (dynamic typing)
  • type() function
  • id() function (memory address)
  • Primitive Types:
    • int (arbitrary precision!)
    • float (IEEE 754)
    • complex (3 + 4j)
    • bool (True, False) — subclass of int!
    • str
    • NoneType (None)
  • Collection Types:
    • list
    • tuple
    • dict
    • set
    • frozenset
    • bytes, bytearray, memoryview
  • Type Conversion (implicit vs explicit)
  • int(), float(), str(), bool(), list(), tuple(), set(), dict()
  • isinstance(), issubclass()

# 1.3 Operators

  • Arithmetic: +, -, *, /, // (floor div), %, **
  • Comparison: ==, !=, <, >, <=, >=
  • Logical: and, or, not
  • Bitwise: &, |, ^, ~, <<, >>
  • Assignment: =, +=, -=, *=, /=, //=, %=, **=, &=, |=, ^=
  • Identity: is, is not
  • Membership: in, not in
  • Walrus Operator (:=) — Python 3.8+
  • Operator Precedence

# 🔁 SECTION 2 — Control Flow

# 2.1 Conditionals

  • if, elif, else
  • Nested conditionals
  • Truthy & Falsy values in Python
  • One-liner ternary: x if condition else y
  • match statement (Python 3.10+) — structural pattern matching

# 2.2 Loops

  • for loop (over any iterable)
  • while loop
  • break, continue, pass
  • else clause on loops (unique to Python!)
  • range() — start, stop, step
  • Nested loops
  • enumerate() ⭐
  • zip() ⭐
  • zip_longest()

# 🧩 SECTION 3 — Functions

# 3.1 Basics

  • def keyword
  • Return values (return)
  • None as default return
  • Docstrings ("""...""")
  • Default Arguments
  • Keyword Arguments
  • Positional-only params (/)
  • Keyword-only params (*)
  • *args (variable positional)
  • **kwargs (variable keyword)
  • Argument order: pos / normal * keyword_only **kwargs

# 3.2 Advanced Functions

  • First-class functions
  • Higher-order functions
  • Lambda functions (lambda x: x*2)
  • Closures ⭐
  • Nested functions
  • Nonlocal & global keywords
  • Recursion + base case
  • Memoization (functools.lru_cache, functools.cache)
  • functools.partial
  • functools.reduce
  • Function annotations (type hints)
  • __doc__, __name__, __annotations__
  • functools.wraps (decorator best practice)

# 3.3 Built-in Functions (must know all!)

abs, all, any, bin, bool, breakpoint, bytearray, bytes, callable,
chr, classmethod, compile, complex, delattr, dict, dir, divmod,
enumerate, eval, exec, filter, float, format, frozenset, getattr,
globals, hasattr, hash, help, hex, id, input, int, isinstance,
issubclass, iter, len, list, locals, map, max, memoryview, min,
next, object, oct, open, ord, pow, print, property, range,
repr, reversed, round, set, setattr, slice, sorted, staticmethod,
str, sum, super, tuple, type, vars, zip, __import__

# 🔡 SECTION 4 — Strings

  • String creation (single, double, triple quotes)
  • Raw strings (r"...")
  • Byte strings (b"...")
  • f-strings (Python 3.6+) ⭐ — f"{name!r:.2f}"
  • f-string = expression support (3.8+ f"{x=}")
  • format() method & format spec
  • % formatting (old style)
  • String immutability
  • String indexing & slicing [start:stop:step]
  • Methods: upper, lower, title, capitalize, swapcase, strip, lstrip, rstrip, split, rsplit, splitlines, join, replace, find, rfind, index, rindex, count, startswith, endswith, isalpha, isdigit, isalnum, isspace, isupper, islower, zfill, center, ljust, rjust, encode, decode, maketrans, translate, expandtabs
  • str.format_map()
  • Multiline strings
  • String interning
  • textwrap module
  • string module constants

# 📋 SECTION 5 — Lists

  • Creating lists
  • Indexing & Slicing
  • Negative indexing
  • List mutability
  • Methods: append, extend, insert, remove, pop, clear, index, count, sort, reverse, copy
  • sorted() vs .sort() (key difference!)
  • list.sort(key=..., reverse=True)
  • List Comprehension ⭐ [expr for x in iterable if cond]
  • Nested list comprehensions
  • * unpacking
  • Shallow vs Deep copy (copy.copy vs copy.deepcopy)
  • List as stack, list as queue (use deque for queue!)
  • del statement

# 📦 SECTION 6 — Tuples

  • Creating tuples (immutability)
  • Single-element tuple: (x,)
  • Packing & Unpacking
  • Extended unpacking (a, *b, c = ...)
  • Named Tuples (collections.namedtuple) ⭐
  • tuple vs list — when to use which
  • Tuple as dict keys (hashable)

# 🗂️ SECTION 7 — Dictionaries

  • Creating dicts ({}, dict())
  • Accessing, updating, deleting keys
  • KeyError handling
  • Methods: get, keys, values, items, update, pop, popitem, clear, copy, setdefault, fromkeys
  • Dictionary Comprehension ⭐ {k: v for k, v in ...}
  • Merging dicts (| operator, Python 3.9+)
  • ** unpacking in dicts
  • Ordered dicts (Python 3.7+ dicts are insertion-ordered)
  • collections.OrderedDict
  • collections.defaultdict ⭐
  • collections.Counter ⭐
  • collections.ChainMap
  • Nested dicts
  • Dict as switch/case replacement

# 🎯 SECTION 8 — Sets

  • Creating sets ({} vs set())
  • Set uniqueness (no duplicates)
  • Methods: add, remove, discard, pop, clear, copy, union, intersection, difference, symmetric_difference, issubset, issuperset, isdisjoint
  • Set operators: |, &, -, ^
  • Set Comprehension {expr for x in iterable}
  • frozenset (immutable, hashable set)
  • Set for O(1) lookups ⭐

# 🏛️ SECTION 9 — OOP (Object-Oriented Programming) ⭐

# 9.1 Classes & Objects

  • class keyword
  • __init__ constructor
  • self parameter
  • Instance variables vs Class variables
  • Instance methods, Class methods (@classmethod), Static methods (@staticmethod)
  • cls vs self

# 9.2 Principles

  • Encapsulation — private (__x), protected (_x)
  • Inheritance — class Child(Parent):
  • Polymorphism — method overriding
  • Abstraction — abc.ABC, @abstractmethod

# 9.3 Advanced OOP

  • Multiple Inheritance
  • MRO (Method Resolution Order) — C3 Linearization ⭐
  • super() ⭐
  • isinstance(), issubclass()
  • Operator Overloading (Dunder/Magic methods)
  • __str__ vs __repr__
  • __len__, __getitem__, __setitem__, __delitem__
  • __iter__, __next__
  • __contains__ (in operator)
  • __call__ (callable objects)
  • __enter__, __exit__ (context managers)
  • __eq__, __lt__, __le__, __gt__, __ge__, __hash__
  • __add__, __mul__, __sub__, __truediv__, etc.
  • __new__ vs __init__
  • __del__ (destructor)
  • __slots__ (memory optimization)
  • __class__, __dict__, __doc__
  • @property, @x.setter, @x.deleter ⭐
  • dataclasses.dataclass (Python 3.7+) ⭐
  • dataclasses.field

# 9.4 Metaclasses

  • What is a metaclass?
  • type as metaclass
  • Custom metaclasses
  • __new__ in metaclass
  • Use cases: singleton, ORM, registration

# 🎁 SECTION 10 — Decorators ⭐

  • What are decorators?
  • Function decorators
  • Class decorators
  • @wraps from functools
  • Decorators with arguments
  • Stacking decorators
  • Built-in decorators: @property, @classmethod, @staticmethod, @abstractmethod, @dataclass
  • Practical use cases: logging, timing, retry, auth, caching

# ⚙️ SECTION 11 — Iterators & Generators ⭐

  • Iterable vs Iterator protocol
  • iter(), next()
  • StopIteration exception
  • Custom Iterators (implementing __iter__ + __next__)
  • Generator Functions (yield) ⭐
  • Generator Expressions (x for x in ...)
  • yield from (Python 3.3+)
  • send() to generators
  • throw(), close() on generators
  • Lazy evaluation benefits
  • Infinite generators
  • itertools module ⭐⭐

# 🔧 SECTION 12 — Context Managers

  • with statement
  • __enter__ & __exit__ protocol
  • Exception handling inside context managers
  • contextlib.contextmanager decorator ⭐
  • contextlib.suppress
  • contextlib.redirect_stdout
  • contextlib.ExitStack
  • Use cases: file handling, locks, DB connections

# ⚠️ SECTION 13 — Exception Handling

  • try, except, else, finally
  • Catching specific exceptions
  • Catching multiple exceptions
  • Exception hierarchy
  • BaseException vs Exception
  • Built-in Exceptions: ValueError, TypeError, KeyError, IndexError, AttributeError, NameError, ImportError, ModuleNotFoundError, OSError, IOError, FileNotFoundError, PermissionError, RuntimeError, StopIteration, GeneratorExit, ArithmeticError, ZeroDivisionError, OverflowError, MemoryError, RecursionError, NotImplementedError, AssertionError, SystemExit, KeyboardInterrupt
  • raise statement
  • raise ... from ... (exception chaining)
  • Custom exceptions (subclassing Exception)
  • assert statement
  • warnings module
  • traceback module
  • sys.exc_info()

# 📁 SECTION 14 — File Handling & I/O

  • open() — modes: r, w, a, rb, wb, r+, x
  • read(), readline(), readlines()
  • write(), writelines()
  • seek(), tell()
  • with open(...) as f: ⭐ (always use this!)
  • File encoding (encoding="utf-8")
  • os.path module
  • pathlib.Path ⭐ (modern way!)
  • shutil — copy, move, delete
  • tempfile — temporary files
  • glob — file pattern matching
  • CSV: csv.reader, csv.writer, csv.DictReader, csv.DictWriter
  • JSON: json.load, json.dump, json.loads, json.dumps
  • pickle — serialization (binary)
  • shelve
  • configparser
  • io.StringIO, io.BytesIO

# 🔢 SECTION 15 — Numbers & Math

  • Integer arithmetic (arbitrary precision)
  • Float precision issues
  • decimal.Decimal (exact decimal math) ⭐
  • fractions.Fraction
  • complex numbers
  • math module: floor, ceil, sqrt, log, log2, log10, exp, pow, factorial, gcd, lcm, sin, cos, tan, pi, e, inf, nan, isnan, isinf, isfinite, comb, perm, prod
  • statistics module: mean, median, mode, stdev, variance, quantiles
  • random module: random, randint, choice, choices, shuffle, sample, seed, uniform, gauss
  • secrets module (cryptographically secure random)
  • Number bases: bin(), oct(), hex(), int(x, base)
  • Bitwise tricks

# 🕐 SECTION 16 — Date & Time

  • datetime module: date, time, datetime, timedelta, timezone
  • datetime.now(), datetime.utcnow()
  • Formatting: strftime(), strptime()
  • timedelta arithmetic
  • Timezone handling: pytz, zoneinfo (Python 3.9+)
  • time module: time(), sleep(), perf_counter(), process_time()
  • calendar module
  • dateutil library (third-party, very useful)

# 🔬 SECTION 17 — Comprehensions (All types)

  • List Comprehension: [expr for x in iter if cond]
  • Dict Comprehension: {k: v for k, v in iter}
  • Set Comprehension: {expr for x in iter}
  • Generator Expression: (expr for x in iter)
  • Nested comprehensions
  • Multiple for clauses
  • Conditional expressions inside comprehensions
  • Performance: comprehension vs loop

# 🧰 SECTION 18 — Standard Library (Must-know modules)

# Data Structures

  • collections: deque, Counter, defaultdict, OrderedDict, namedtuple, ChainMap, UserDict, UserList
  • heapq: min-heap operations, heappush, heappop, heapify, nlargest, nsmallest
  • bisect: binary search on sorted lists, bisect_left, bisect_right, insort
  • array: typed arrays

# Functional

  • functools: reduce, partial, lru_cache, cache, wraps, total_ordering, singledispatch
  • itertools ⭐⭐: count, cycle, repeat, chain, islice, zip_longest, product, permutations, combinations, combinations_with_replacement, groupby, starmap, takewhile, dropwhile, filterfalse, accumulate, tee, compress, pairwise
  • operator: itemgetter, attrgetter, methodcaller

# OS & System

  • os: getcwd, chdir, listdir, mkdir, makedirs, remove, rmdir, rename, environ, getenv, path, walk, stat
  • sys: argv, path, exit, stdin, stdout, stderr, version, platform, modules, getrecursionlimit, setrecursionlimit
  • subprocess: run, Popen, call, check_output
  • platform
  • signal
  • shutil
  • pathlib

# Text & String

  • re (Regular Expressions) ⭐
  • string
  • textwrap
  • difflib
  • unicodedata

# Networking & Web

  • http.client, http.server
  • urllib: urllib.request, urllib.parse, urllib.error
  • socket
  • ssl
  • email, smtplib, imaplib
  • html, html.parser
  • xml.etree.ElementTree

# Concurrency

  • threading
  • multiprocessing
  • asyncio ⭐
  • concurrent.futures
  • queue

# Other Important

  • abc (Abstract Base Classes)
  • copy
  • pprint
  • reprlib
  • enum
  • dataclasses
  • typing
  • contextlib
  • warnings
  • logging
  • unittest
  • argparse
  • configparser
  • hashlib
  • hmac
  • secrets
  • uuid
  • struct
  • io
  • inspect
  • dis
  • ast
  • tokenize
  • gc (garbage collector)
  • weakref
  • tracemalloc

# 🔄 SECTION 19 — Regular Expressions (`re` module)

  • re.match(), re.search(), re.findall(), re.finditer()
  • re.sub(), re.subn()
  • re.split()
  • re.compile() — compiled patterns
  • Flags: re.IGNORECASE, re.MULTILINE, re.DOTALL, re.VERBOSE, re.ASCII
  • Patterns: ., ^, $, *, +, ?, {n,m}, [], [^], \d, \D, \w, \W, \s, \S, \b, \B
  • Groups: (), (?:...), (?P<name>...), (?P=name)
  • Lookahead: (?=...), (?!...)
  • Lookbehind: (?<=...), (?<!...)
  • Match object methods: group(), groups(), groupdict(), start(), end(), span()
  • Greedy vs Non-greedy (*?, +?, ??)
  • Raw strings with regex

# ⚡ SECTION 20 — Async Python ⭐

# 20.1 Concurrency Concepts

  • Concurrency vs Parallelism
  • I/O-bound vs CPU-bound tasks
  • GIL (Global Interpreter Lock) — what it is, impact
  • Threading for I/O-bound
  • Multiprocessing for CPU-bound
  • Asyncio for I/O-bound (single-threaded!)

# 20.2 `asyncio`

  • async def — coroutines
  • await keyword
  • asyncio.run()
  • asyncio.create_task()
  • asyncio.gather() ⭐
  • asyncio.wait()
  • asyncio.wait_for() (timeout)
  • asyncio.sleep()
  • asyncio.Queue
  • asyncio.Event, asyncio.Lock, asyncio.Semaphore
  • Event Loop: asyncio.get_event_loop()
  • async for (async iterators)
  • async with (async context managers)
  • __aiter__, __anext__, __aenter__, __aexit__
  • Async generators
  • asyncio.shield()
  • asyncio.timeout() (Python 3.11+)
  • Task cancellation
  • Exception handling in tasks

# 20.3 Threading

  • threading.Thread
  • daemon threads
  • threading.Lock, RLock, Semaphore, Event, Condition, Barrier
  • Thread-local data (threading.local)
  • threading.Timer
  • concurrent.futures.ThreadPoolExecutor ⭐

# 20.4 Multiprocessing

  • multiprocessing.Process
  • multiprocessing.Pool ⭐ — map, starmap, apply_async
  • multiprocessing.Queue, Pipe
  • multiprocessing.Value, Array (shared memory)
  • multiprocessing.Manager
  • concurrent.futures.ProcessPoolExecutor ⭐
  • multiprocessing.shared_memory (Python 3.8+)

# 🔍 SECTION 21 — Type Hints & Typing Module (Python 3.5+)

  • Why type hints?
  • Basic annotations: int, str, float, bool, None
  • List, Dict, Tuple, Set, Optional, Union
  • Python 3.9+ built-in generics: list[int], dict[str, int]
  • Optional[X] = X | None (Python 3.10+)
  • Union[X, Y] = X | Y (Python 3.10+)
  • Any
  • Callable
  • TypeVar (generics)
  • Generic class
  • Protocol (structural subtyping) ⭐
  • TypedDict
  • Literal
  • Final
  • ClassVar
  • Annotated
  • overload
  • TYPE_CHECKING
  • cast()
  • ParamSpec, Concatenate
  • TypeAlias (Python 3.10+)
  • TypeGuard
  • Self type (Python 3.11+)
  • Never, NoReturn
  • Static type checkers: mypy, pyright, pytype

# 🧠 SECTION 22 — Functional Programming in Python

  • Pure functions
  • Immutability
  • map(), filter(), zip(), enumerate()
  • functools.reduce()
  • Lambda functions
  • Closures
  • Currying (functools.partial)
  • Function composition
  • functools.singledispatch (generic functions)
  • Monads (basic concept)
  • Lazy evaluation with generators

# 🧪 SECTION 23 — Testing

  • unittest — built-in test framework
    • TestCase, setUp, tearDown, setUpClass, tearDownClass
    • Assertions: assertEqual, assertNotEqual, assertTrue, assertFalse, assertRaises, assertIn, assertIsNone, assertAlmostEqual
    • Test Discovery
    • unittest.mock: Mock, MagicMock, patch, call
  • pytest ⭐⭐ (industry standard)
    • Fixtures (@pytest.fixture)
    • Parametrize (@pytest.mark.parametrize)
    • conftest.py
    • pytest.raises
    • Plugins: pytest-cov, pytest-asyncio, pytest-mock
    • Markers
  • doctest — tests in docstrings
  • TDD (Test Driven Development)
  • Code Coverage: coverage.py
  • Property-based testing: hypothesis

# 🚀 SECTION 24 — Modules & Packages

  • import statement
  • from ... import ...
  • import ... as ...
  • __init__.py
  • Relative imports (., ..)
  • __all__ variable
  • Module __name__, __file__, __package__
  • Package structure
  • Namespace packages (PEP 420)
  • importlib
  • pkgutil
  • sys.path manipulation
  • Circular imports (problem & solution)
  • Lazy imports
  • importlib.reload()

# 📡 SECTION 25 — Networking & Web

  • socket programming (TCP, UDP)
  • http.server (simple server)
  • urllib (basic requests)
  • requests library ⭐ (industry standard)
    • GET, POST, PUT, DELETE
    • Sessions, cookies, headers
    • Timeouts, retries
    • Authentication
    • File upload
  • httpx (async support, modern)
  • aiohttp (async HTTP)
  • WebSockets: websockets library
  • REST API consumption
  • json parsing

# 🌐 SECTION 26 — Web Frameworks (Overview)

  • Flask — micro framework
    • Routes, views, templates (Jinja2)
    • Request/Response
    • Blueprints
    • Extensions: Flask-SQLAlchemy, Flask-Login
  • Django — batteries included
    • MTV (Model-Template-View)
    • ORM, Admin, Auth, Forms, Migrations
    • settings.py, urls.py, views.py, models.py
  • FastAPI ⭐ (modern, async, automatic docs)
    • Path params, query params, body
    • Pydantic models
    • Dependency injection
    • OpenAPI/Swagger auto-docs
    • async first
  • Starlette (ASGI framework, FastAPI is built on it)
  • WSGI vs ASGI

# 🗄️ SECTION 27 — Databases & ORM

  • Raw SQL with sqlite3 (built-in)
  • psycopg2 (PostgreSQL)
  • pymysql / mysql-connector (MySQL)
  • SQLAlchemy ⭐ (industry ORM)
    • Core vs ORM
    • Models, Sessions, Queries
    • Relationships, Joins
    • Migrations with Alembic
  • Tortoise ORM (async ORM)
  • Peewee (lightweight ORM)
  • NoSQL: pymongo (MongoDB)
  • Redis: redis-py
  • databases library (async queries)

# 📊 SECTION 28 — Data Science Stack (Overview)

  • NumPy ⭐ — N-dimensional arrays, vectorization, broadcasting
  • Pandas ⭐ — DataFrame, Series, data manipulation
  • Matplotlib — 2D plotting
  • Seaborn — statistical visualization
  • Plotly — interactive charts
  • SciPy — scientific computing
  • Scikit-learn — Machine Learning
  • Jupyter Notebook / JupyterLab
  • Polars (modern, fast DataFrame library)

# 🤖 SECTION 29 — Machine Learning & AI (Python's Domain)

  • scikit-learn — classification, regression, clustering, preprocessing, pipelines
  • Deep Learning:
    • TensorFlow / Keras
    • PyTorch ⭐ (industry favorite for research)
  • transformers (HuggingFace) — NLP, LLMs
  • LangChain, LlamaIndex — LLM apps
  • OpenAI Python SDK
  • Anthropic Python SDK 😉
  • opencv-python — Computer Vision
  • NLTK, spaCy — NLP

# 🛠️ SECTION 30 — Packaging & Distribution

  • setup.py (old way)
  • pyproject.toml ⭐ (modern way — PEP 517/518)
  • setuptools, poetry, hatch, flit
  • pip — install, uninstall, upgrade, freeze, install -r
  • requirements.txt
  • Virtual environments: venv, virtualenv, conda
  • pipenv
  • poetry ⭐ (dependency management + packaging)
  • uv ⭐ (blazing fast, modern — 2024)
  • Uploading to PyPI: twine
  • __version__
  • Entry points & scripts
  • Building: python -m build

# 🔐 SECTION 31 — Security

  • secrets module (secure random)
  • hashlib (SHA256, MD5, etc.)
  • hmac
  • ssl
  • cryptography library
  • bcrypt, argon2 (password hashing)
  • SQL Injection prevention (parameterized queries)
  • Input validation
  • bandit (security linter for Python)
  • .env files & python-dotenv ⭐ (never hardcode credentials!)

# ⚡ SECTION 32 — Performance & Optimization

  • Profiling: cProfile, profile, pstats
  • timeit module ⭐
  • line_profiler
  • memory_profiler
  • Optimization techniques:
    • Avoid global variables
    • Use local variables inside loops
    • List comprehensions over loops
    • Generators for large data
    • __slots__ in classes
    • numpy vectorization instead of loops
    • Caching: functools.lru_cache
    • Lazy imports
  • Fast alternatives:
    • PyPy (JIT compiled Python)
    • Cython (Python → C)
    • Numba (JIT for numerical code)
    • ctypes, cffi (C extensions)
    • mypyc
  • GIL workarounds
  • multiprocessing for CPU-bound
  • asyncio for I/O-bound

# 🔍 SECTION 33 — Introspection & Metaprogramming

  • dir(), vars(), type(), id()
  • inspect module ⭐ — signature, getsource, isfunction, isclass, ismethod, getmembers, stack
  • getattr, setattr, hasattr, delattr
  • __dict__, __class__, __bases__, __mro__
  • __getattr__, __getattribute__, __setattr__, __delattr__
  • Descriptors (__get__, __set__, __delete__, __set_name__)
  • Metaclasses deep dive
  • type() to create classes dynamically
  • Class decorators
  • __init_subclass__
  • abc.ABCMeta
  • __slots__
  • ast module (Abstract Syntax Tree)
  • dis module (bytecode disassembly)
  • Code objects
  • exec(), eval(), compile() — and why to avoid them

# 🧵 SECTION 34 — Design Patterns in Python

  • Creational: Singleton, Factory, Abstract Factory, Builder, Prototype, Borg
  • Structural: Adapter, Bridge, Composite, Decorator, Facade, Flyweight, Proxy
  • Behavioral: Chain of Responsibility, Command, Iterator, Mediator, Memento, Observer, State, Strategy, Template Method, Visitor
  • Pythonic patterns: Context Manager, Descriptor, Generator-as-coroutine, Mixin

# 🧹 SECTION 35 — Code Quality & Best Practices

  • PEP 8 compliance
  • Linters: flake8, pylint, ruff ⭐ (fastest, modern)
  • Formatters: black ⭐, autopep8, isort
  • Type checkers: mypy, pyright ⭐
  • Security: bandit
  • Pre-commit hooks: pre-commit
  • Docstrings: Google style, NumPy style, Sphinx style
  • sphinx — documentation generation
  • Clean code principles in Python
  • SOLID principles (Python examples)
  • DRY, KISS, YAGNI

# 📝 SECTION 36 — Logging

  • logging module ⭐
  • Log levels: DEBUG, INFO, WARNING, ERROR, CRITICAL
  • basicConfig()
  • Logger, Handler, Formatter, Filter
  • File handlers, rotating handlers
  • logging.config.dictConfig()
  • Structured logging: structlog
  • loguru (modern, developer-friendly) ⭐

# 🔧 SECTION 37 — CLI Tools & Scripting

  • sys.argv
  • argparse ⭐ — add_argument, parse_args, subcommands
  • getopt
  • click ⭐ (best CLI library)
  • typer ⭐ (click + type hints, modern)
  • rich — beautiful terminal output ⭐
  • colorama — colored output
  • tqdm — progress bars
  • Shell scripting with Python (subprocess, os)
  • invoke — task runner

# 🌍 SECTION 38 — Environment & Config Management

  • Environment variables (os.environ, os.getenv)
  • python-dotenv ⭐ — .env files
  • configparser — .ini files
  • pydantic-settings — type-safe config ⭐
  • dynaconf
  • TOML config (tomllib built-in Python 3.11+)
  • 12-Factor App principles for Python

# 🏆 Extra Gyan By Your Bhai 🧠

Bhai sun, Python bohot bada hai — isko sab ek saath mat sikho. Ek proven roadmap deta hoon:

# 🗺️ Learning Roadmap

Phase 1 — Core Python (4-6 weeks)

Section 1, 2, 3, 4, 5, 6, 7, 8, 13, 14

Phase 2 — Intermediate (3-4 weeks)

Section 9 (OOP ⭐), 10 (Decorators), 11 (Generators), 12 (Context Managers), 17 (Comprehensions), 18 (Stdlib)

Phase 3 — Advanced Python (3-4 weeks)

Section 19 (Regex), 20 (Async ⭐), 21 (Type Hints), 24 (Modules), 32 (Performance), 33 (Metaprogramming)

Phase 4 — Ecosystem (pick your path)

Web Dev → Section 25, 26, 27
Data Science → Section 28, 29
DevOps/Scripting → Section 37, 38

Phase 5 — Professional (always ongoing)

Section 22, 23 (Testing ⭐), 30 (Packaging), 31 (Security), 34 (Design Patterns), 35 (Code Quality), 36 (Logging)

# ⚠️ Top Mistakes Python Beginners Make

Mistake Reality
Mutable default arguments def f(x=[]) Biggest Python gotcha!
== se None check karna Always use is None
Bare except: Always catch specific exceptions
import * use karna Never do this in production
+ se string concatenation in loop Use "".join() instead
Not using virtual environments Always use venv/poetry
time.sleep() in async code Use asyncio.sleep()
Using pickle for untrusted data Security risk!

# 🔥 Python-Specific Power Features

Ye sab sikhle toh real Pythonista ban jaoge:

  • itertools ← underrated gem, master this
  • collections module ← use karo! Counter, defaultdict, deque
  • Generator expressions for memory efficiency
  • dataclasses ← modern replacement for verbose classes
  • Protocol ← duck typing ka type-safe version
  • functools.lru_cache ← instant memoization
  • pathlib ← never use os.path again
  • f-strings ← best string formatting, period
  • walrus operator := ← write tighter loops
  • match statement ← structural pattern matching (3.10+)

Made with 🐍 — Your Bhai's Complete Python Bible