Dev Blog

Summary ​

Conclusions ​

An iterator separates obtaining the next element from processing it. A generator implements this contract with yield, while itertools combines ready-made traversal patterns. A lambda suits a short local rule; a decorator suits shared behavior around a call. In both cases, readability and an explicit contract matter more than reducing the line count.

Self-check questions ​

  1. How does an iterable differ from an iterator?
  2. Who handles StopIteration in a for loop?
  3. When does a generator function's body start executing?
  4. What state is preserved after yield?
  5. What do yield from, send, and close do?
  6. Why might summing a generator a second time give zero?
  7. How does takewhile differ from filter?
  8. When is sorting before groupby necessary, and when is it harmful?
  9. How does batched handle an incomplete final batch?
  10. What does sys.getsizeof actually measure?
  11. Why might a closure in a loop see the final value?
  12. How do you choose between map, a comprehension, and reduce?
  13. When is a decorator applied, and when does its wrapper execute?
  14. Why are wraps and ParamSpec needed?
  15. How does decorator order change retries and timing?
  1. Functional programming tools: https://docs.python.org/3.14/howto/functional.html.
  2. Iterators: https://docs.python.org/3.14/library/itertools.html.
  3. Decorators and caching: https://docs.python.org/3.14/library/functools.html.
  4. Operations as functions: https://docs.python.org/3.14/library/operator.html.