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.