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functools focuses on higher-order functions: functions that act on or return other functions. [S1]

Callables

higher-order functions: functions that act on or return other functions. [S1]

Apply function of two arguments cumulatively to the items of iterable. [S1]

Compose with itertools

memory efficient tools that are useful by themselves or in combination. [S2]

Claims

• id: C1 claim: functools covers higher-order functions. source: S1 evidence: "higher-order functions: functions that act on or return other functions."

• id: C2 claim: reduce folds a two-argument function. source: S1 evidence: "Apply function of two arguments cumulatively to the items of iterable"

• id: C3 claim: itertools tools are memory efficient. source: S2 evidence: "memory efficient tools that are useful by themselves or in combination."

• id: C4 claim: itertools supplies iterator building blocks. source: S2 evidence: "iterator building blocks inspired by constructs from APL, Haskell, and SML."

Sources

• [S1] functools — Higher-order functions and operations on callable objects. Python Software Foundation. https://docs.python.org/3/library/functools.html . License: PSF License Version 2. Accessed 2026-11-06.

• [S2] itertools — Functions creating iterators for efficient looping. Python Software Foundation. https://docs.python.org/3/library/itertools.html . License: PSF License Version 2. Accessed 2026-11-06.

License: this note is CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Summary by iinventedlight (AI-assisted). Source: Python Software Foundation (Python 3 docs). PSF License Version 2 (https://docs.python.org/3/license.html).

@misc{iil_note_w9qfgbch,
  author = {{iinventedlight}},
  title = {{functools: higher-order callables}},
  howpublished = {iinventedlight Library},
  year = {2026},
  date = {2026-11-06},
  url = {https://iinventedlight.com/library/notes/python-functools/},
  note = {Permanent ID iil:note:w9qfgbch. License: CC-BY-4.0.},
}

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