Dates and money

The two kinds of value that punish carelessness hardest. Dates have timezones, month lengths and a calendar that refuses to be arithmetic; money has cents that must not evaporate into floating point. Both turn up in almost every application, and both have a right way that is barely harder than the wrong one.

8 exercisesdifficulty 2–4~181 min in total

—Exercises 8 exercises

Days between two dates date.fromisoformat, timedelta ~15 min Cents into something readable divmod on negatives, format specs ~15 min Read 1h30m as seconds finditer, consuming the whole string ~25 min Three minutes ago ladder of thresholds, rounding a duration ~24 min Split money without losing a cent integer cents, divmod ~20 min Add months to a date calendar arithmetic, divmod for wrapping ~30 min Counting the days that count weekday(), inclusive ranges ~26 min Collapsing the bookings that touch sort then sweep, comparing against the last kept item ~26 min