Common Standard Library Modules (No Install Required)¶

These modules are built into Python and do not need to be installed. They are available automatically in every Python environment.

Note: These modules are part of the Python Standard Library. Do not add them to pyproject.toml or requirements.txt.

Data Handling¶

Module	Purpose
`json`	Handle JSON data (read, write, serialize).
`csv`	Read and write CSV files.
`sqlite3`	Work with SQLite databases (included with Python).

Filesystem and System Access¶

Module	Purpose
`pathlib`	Work with filesystem paths using object-oriented syntax.
`os`	Interact with the operating system (file paths, environment variables).
`sys`	Access system-specific parameters and functions.
`urllib`	Basic URL handling and data fetching (useful with or without `requests`).

Mathematics and Randomness¶

Module	Purpose
`math`	Mathematical functions (`sqrt`, `log`, etc.).
`statistics`	Basic statistics (mean, median, stdev).
`random`	Generate random numbers.
`time`	Time-based functions (sleep, timing).
`datetime`	Date and time manipulation.

Logging and Pattern Matching¶

Module	Purpose
`logging`	Structured and configurable logging.
`re`	Regular expressions and pattern matching.
`pprint`	Pretty-print complex or nested data structures.

Advanced Containers and Typing¶

Module	Purpose
`collections`	Specialized containers (`Counter`, `defaultdict`, etc.).
`typing`	Type hints and static type checking.

Testing (Modern Context)¶

While Python includes unittest by default, most modern projects use pytest (a third-party tool) for its simplicity and better reporting. pytest is not part of the standard library and must be installed separately.

Summary

All modules listed above are available automatically with any standard Python 3 installation. They require no installation, no network access, and are safe to import in all environments.