1. Historical how and why of hash tables
2.
3. But what?
4. Perfect!
5.
8. We have a winner!
9. Early sightings
10. * Basic idea:
11. * The key is almost always some kind of *string*
12. Basic operations
13. * Python:
15. Hashes changed the way we program
16. handle_article(path, category, article_body) {
17. category_count = new Hash();
18. No problem:
19. Another example:
20. How did we do this before?
21. * Big drawback of assoc lists:
22. 2-3 trees
23. Red-black trees
24. AVL trees
25. Hash tables
26. SNOBOL
27. How hashes work
28. Obvious problems
29. How does the mapping work?
30. Balls in bins
31. Collisions
32. What happens when the array fills up?
33. Collisions
34. Deletion
35. Thank you!