Standard Library Guide

os — Operating System Interface

File paths, environment variables, process management.

sys — System Parameters

Interpreter settings, stdin/stdout, exit codes.

pathlib — Object-Oriented Paths

Modern path manipulation.

json — JSON Encoder/Decoder

Serialize Python objects to JSON.

csv — CSV File Reading and Writing

Read and write CSV files.

datetime — Date and Time

Dates, times, timedeltas, formatting.

collections — Specialized Containers

Counter, deque, defaultdict, namedtuple.

itertools — Iterator Functions

chain, combinations, permutations, cycle.

functools — Higher-Order Functions

lru_cache, partial, wraps.

re — Regular Expressions

Pattern matching and substitution.

subprocess — Subprocess Management

Run external commands safely.

threading — Thread-Based Parallelism

Threads for I/O-bound concurrency.

multiprocessing — Process-Based Parallelism

Bypass the GIL with processes.

asyncio — Asynchronous I/O

Coroutines, event loops, async/await.

socket — Low-Level Networking

TCP/UDP sockets.

http.server — HTTP Servers

Simple HTTP server for development.

urllib — URL Handling

request, parse, error modules.

sqlite3 — SQLite Database

Embedded SQL database.

logging — Logging Facility

Structured application logging.

unittest — Unit Testing

Built-in test framework.

argparse — CLI Argument Parsing

Command-line interfaces.

typing — Type Hints

Static typing support.

dataclasses — Data Classes

Boilerplate-free data containers.

enum — Enumerations

Named constant sets.

abc — Abstract Base Classes

Define interfaces.

contextlib — Context Utilities

contextmanager, suppress, redirect_stdout.

copy — Shallow and Deep Copy

copy.copy vs copy.deepcopy.

math — Mathematical Functions

sqrt, sin, log, ceil, floor.

random — Pseudo-Random Numbers

random, shuffle, choice, sample.

secrets — Secure Random

Cryptographically strong tokens.

hashlib — Secure Hashes

MD5, SHA256 hashing.

hmac — Message Authentication

Keyed hashing for signatures.

tempfile — Temporary Files

Auto-cleaned temp files and dirs.

shutil — High-Level File Ops

copy, move, rmtree, disk_usage.

glob — Pathname Pattern Matching

Find files by pattern.

gzip — GZIP Compression

Compress and decompress files.

pickle — Python Object Serialization

Serialize objects (trusted data only!).

io — Core I/O Tools

StringIO, BytesIO in-memory streams.

struct — Binary Data

Pack/unpack C structs.

base64 — Base64 Encoding

Encode binary as ASCII.

html — HTML Utilities

Escape/unescape HTML entities.

xml.etree.ElementTree — XML

Parse and build XML.

configparser — INI Files

Read .ini configuration.

tomllib — TOML (3.11+)

Parse TOML config files.

zoneinfo — Timezones

IANA timezone database.

calendar — Calendar Utilities

Month/weekday helpers.

decimal — Decimal Arithmetic

Exact decimal math for finance.

fractions — Rational Numbers

Exact fractions.

statistics — Statistics

mean, median, stdev, quantiles.

heapq — Heap Queue

Priority queues.

bisect — Binary Search

Sorted list insertion/search.

array — Typed Arrays

Compact numeric arrays.

queue — Synchronized Queues

Thread-safe FIFO/LIFO queues.

weakref — Weak References

References that don't prevent GC.

gc — Garbage Collector

Inspect and control GC.

inspect — Live Object Inspection

Introspect functions, classes, stack.

ast — Abstract Syntax Trees

Parse Python source to AST.

dis — Disassembler

View bytecode instructions.

traceback — Stack Traces

Format exception tracebacks.

warnings — Warning Control

Filter and issue warnings.

getpass — Secure Password Input

Hidden terminal input.

platform — Platform Info

OS, Python version, machine.

uuid — UUID Objects

Universally unique identifiers.

ipaddress — IP Addresses

IPv4/IPv6 manipulation.

email — Email Handling

Parse and build email messages.

mimetypes — MIME Types

Guess file MIME types.

zipfile — ZIP Archives

Read and write zip files.

tarfile — TAR Archives

Read/write tar archives.

fnmatch — Filename Matching

Shell-style wildcards.

Path.glob Patterns

Glob patterns via pathlib.

codecs — Codec Registry

Encode/decode text encodings.

locale — Localization

Locale-specific formatting.

pdb — Python Debugger

Interactive debugging.

cProfile — Profiler

Profile Python programs.

timeit — Measure Execution Time

Benchmark small code snippets.

signal — Signal Handlers

Handle OS signals.

mmap — Memory-Mapped Files

Map files into memory.

selectors — I/O Multiplexing

High-level select interface.

ssl — TLS/SSL Wrapper

Secure socket connections.

wsgiref — WSGI Reference

Minimal WSGI server for testing.