AI APIs communicate in JSON. Data pipelines use lists and dicts. Today you master Python's core data structures and learn to move fluently between Python objects and JSON — the skill every AI integration requires.
By the end of this lesson you will create and manipulate lists and dictionaries, convert between Python objects and JSON with json.loads and json.dumps, use list comprehensions, and pick the right data structure for a given problem.
lists is the foundation of Day 2. Every concept that follows builds on the mental model you establish here. The most effective approach is to understand the principle first, then apply it — skipping straight to implementation creates gaps that compound into confusion later.
Work through each example in this lesson sequentially. The concepts connect, and the order is deliberate. If something is unclear, slow down at that point rather than pushing past it — a ten-minute pause now saves hours of debugging later.
Understanding lists requires seeing it in motion. The code below is not a complete application — it is a minimal, working illustration of the key mechanism. Study the pattern, run it, break it deliberately, then fix it. That cycle builds real comprehension.
Once the basic pattern works, the logical next step is dictionaries. This is where the abstraction becomes useful — you move from understanding the mechanism to applying it to real problems. The transition is usually smaller than it feels. Most of the hard work happened in Section 1.
JSON completes today's picture. It is where lists and dictionaries converge into a pattern you can apply to novel problems. This integration step is often where the day's learning consolidates — if the earlier sections felt abstract, this one typically makes them click.
Implementing lists alone handles the happy path. Real systems encounter edge cases, invalid input, and unexpected state. Missing dictionaries means missing those guards.
Combining lists with dictionaries gives you a complete, defensible implementation. The extra lines cost ten minutes; the robustness they add is worth hours of debugging time.
Several mistakes appear consistently when engineers encounter Data Structures — Lists, Dicts, JSON for the first time. Recognizing them now costs nothing; encountering them in production costs hours.
Two intensive days (Thu–Fri) with an instructor who has taught thousands of engineers. Cohorts in 5 cities, June–June–October 2026 (Thu–Fri).
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