Reviewed by Aditya Kumar · Last reviewed 2026-03-24
**Core Operations:** Indexing, slicing (lst[i:j:k]), append, extend, insert, remove, pop, sort, reverse. Membership (in) is O(n); for repeated lookup use set. **Gotchas:** lst.reverse() and lst.sort() mutate in-place, return None. reversed(lst) and sorted(lst) return new...
Core Operations: Indexing, slicing (lst[i:j:k]), append, extend, insert, remove, pop, sort, reverse. Membership (in) is O(n); for repeated lookup use set.
Gotchas: lst.reverse() and lst.sort() mutate in-place, return None. reversed(lst) and sorted(lst) return new iterable/list. lst += [1] mutates; lst = lst + [1] creates new. Slice assignment lst[1:3] = [a,b] can change length.
Production: Prefer list comprehensions over manual loops. Use bisect for sorted lists. For parsing: list of dicts from CSV/JSON rows; avoid modifying while iterating.
Red Flag: Confusing lst.sort() (returns None) with sorted(lst). Pro-Move: 'For large lookups we convert to set—O(1) membership for deduplication checks.'
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