11. Useful Standard Library

Grab-bag of batteries-included modules you’ll reach for frequently.

Question: Name some useful modules in the Python standard library.

Answer:

• collections: Provides advanced data structures like Counter (for counting hashable objects), defaultdict (a dictionary that provides a default value for missing keys), and deque (a double-ended queue).

• datetime: For working with dates and times.

• json: For parsing and generating JSON data.

• os and pathlib: For interacting with the operating system and file paths.

• random: For generating random numbers.

• itertools: Building blocks for efficient loops, e.g., chain, cycle, groupby.

• logging: Configurable application logging; prefer over print in real apps.

• functools: Higher-order functions like lru_cache (memoization), partial (pre-fill arguments), and wraps (preserve metadata in decorators).

• csv: Read and write CSV files interoperably.

• statistics: Basic stats like mean, median, stdev.

• contextlib: Tools for context managers, e.g., contextmanager, ExitStack, suppress.

• re: Regular expressions for text parsing.

• typing: Type hints like TypedDict, Protocol, Literal.