12. Short Q&A Prompts

Quick drills to practice clarity and coverage under time pressure.

Tip: when answering, define the concept in 1 sentence, give a tiny example, and note 1–2 practical trade-offs.

• What does s[a:b:c] mean and how do negative indices work?
• Why are mutable default arguments dangerous and how do you avoid them?
• List vs tuple: when would you choose each?
• How do you copy a list safely? Shallow vs deep copy.
• What’s the difference between is and ==? Give an example.
• Explain LEGB with a quick example.
• EAFP vs LBYL: when is each preferable?
• What does enumerate return? When would you use zip?
• Write a list comprehension and a generator expression that produce even numbers 0..8.
• How do context managers help? Show the with open(...) pattern.
• Threading vs multiprocessing vs asyncio: pick one for I/O vs CPU.
• Big-O for dict lookup and list insert at the beginning.