Create Python lists, read positions from either end, replace existing items, and use len() safely.

Grow lists with append, extend and insert; remove values or positions with remove and pop.

Extract list windows with slices, use steps and negative bounds, and avoid unwanted mutation through copies.

Use ordered immutable records, tuple indexing, packing and unpacking, and safe replacements.

Use unique collections for membership, safe updates, and comparisons between groups.

Create key-value mappings, inspect keys, update entries, and avoid missing-key errors.

Read optional fields with get and iterate keys, values, and key-value pairs.

Navigate, update, and process nested collections with safe optional lookups.

Build filtered lists, count repeated values, and group records into dictionary lists.

Distinguish in-place sorting, sorted copies, descending order, and reversing.

Choose and combine lists, tuples, sets, and dictionaries in reusable processing workflows.