What is EAFP vs LBYL in Python?

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Two error-handling philosophies:

- **EAFP — 'Easier to Ask Forgiveness than Permission':** just *do* the operation and catch the exception if it fails. `try: value = d[key] except KeyError: ...`. This is the **Pythonic** default.
- **LBYL — 'Look Before You Leap':** *check* preconditions first, then act. `if key in d: value = d[key]`.

Why Python favors EAFP:

1. **Avoids race conditions (TOCTOU):** with LBYL the state can change *between* the check and the use (a file you checked exists gets deleted; a dict key gets popped by another thread). EAFP acts atomically and handles the failure.
2. **Often clearer and faster on the happy path** — no duplicate lookups, and exceptions are cheap when they don't fire.

LBYL still has its place (cheap, side-effect-free checks; validating user input up front; avoiding an expensive operation). But for dict access, attribute access, file I/O and conversions, EAFP wins.

**Interview tip:** name both acronyms, say EAFP is idiomatic Python, and give th

What is EAFP vs LBYL in Python?

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