CSC151.01 2015S, Class 23: Revisiting Lists

Overview

Preliminaries

Review session Monday at 7:00 p.m.
Office hours today at 10:00 a.m.
- http://rebelsky.youcanbook.me
One of your classmates passed along the following article which you might find interesting.
- http://www.wired.com/2015/02/science-one-agrees-color-dress/
Prospies Monday! Be prepared for special activities.
Friday PSA
- In making choices this weekend, please make sure that Nobody Gets Hurt (including you).
- There are a lot of illnesses going around campus. Rest will help you avoid them better than almost anything. (I'm telling myself the same thing.)

Homework 6 is optional so that you have time to get rest.
- Due Tuesday at 10:30 p.m.
- It will make up for one other homework assignment, provided it is higher than some other homework assignment.
Exam 2 to be assigned on Tuesday.
No lab writeup for today.
Reading for Monday: Recursion Basics
- Recursion Basics
- A cool and different topic that we'll be talking about through spring break (and the rest of the semester).
Fun with HW5
- Create a large list of numbers (iota 1000)
- Convert each number to an (x,y) coordinate (lambda (i) (mod (* 11 i) (image-width))) (lambda (i) (mod (* 13 i) (image-height)))

Julia's radio show, "The Hot Box". Wednesday night/Thursday morning 1:00-2:00 a.m.
Host a prospie.
Indoor Track today and Saturday. Support Grinnell Pride!
Neverland Players Friday and Saturday at 7:00, Sunday at 1:30 and 7:00
Grinnell Singers Sunday at 2pm. Handel's Esther. Maybe Sebring Lewis.
Orchestra a week from Saturday at 2pm in Sebring-Lewis. Musicals and Show Tunes and Soloists.

When you're done with the quiz, bring up the lab, read through it, and wait for your partner.

Pairs (cons) can be used to build lists, but they can also be used to build things that aren't lists.
If you have something that seems to be a list, but has a period in the middle, it's not a list.
Since Erin seems to enjoy stupid wordplay, we used to use the following names for the values in problem 3: one-two, won-too, want-to.
Pronounciation:
- "cdr" = "could-er" or "cudder"
- "cadr" = "cahd-er"
- "cddr" = "could-ood-er"
- "car" = "cah"

We can manipulate lists with cons, car, and cdr
Computer scientists count starting at 0.
Lists provide mechanisms for storing collections of related data.
- Characteristics of a shape.
- Ratings of a movie.
- Information on a course at Grinnell.
- Etc.
If you know the form of the list, you can work with the data.