Module 33

Grouping data with hash maps

Lists as the values of a hash map. Adding to the right list and creating it the first time a key is seen, counting and grouping by a key, a class that keeps its data in groups, and why finding a key in a hash map stays fast however big the map grows. MOOC sections 8.4 and 8.5.

Steps

1. A list as a value
2. Counting and grouping
3. Groups inside a class
4. Fast lookups, and the end of part 8