Nested Data

Real data is almost always nested: lists of records, dicts of dicts.

Access

• data[0]["field"] — chain subscripts left to right
• Always think about what type each step returns

Useful pattern: dict.setdefault

d.setdefault(key, []).append(x) — start an empty list under key if missing, then append. The bread-and-butter of grouping.

Try it

1. Build a list of skills sorted by how many users have them.
2. Find users who know "git".