T-Th 9:05
or
T-Th 11:15
in Olin 155

CS 1110: Introduction to Computing Using Python

Fall 2017

# Lecture Summaries

If you want to see what future lectures in this class will be, you should look at the syllabus page.

## Week 15

### 30 November (Thursday): Course Wrap-Up

[Presentation]

Hopefully you have enjoyed this course. Assuming that you have, today we discuss your options about what to do next in computer science.

### Lab 13: Sequence Algorithms

[Instructions]

This is the last lab of the course, but it is not required. It serves as extra credit; you can "get back" a lab by completing this one. It covers the major topics with sequence algorithms that will appear on the final. Therefore, lab is a very useful way to study for the final exam.

### 28 November (Tuesday): Searching and Sorting

[Handout]      [Presentation]
Demos
algorithms.py

Today we complete our discussion of loop invariants and show how to use them to implement sorting. This is the last lecture covering material on the exam.

## Week 14

### 21 November (Tuesday): Sequence Algorithms (cont)

[Handout]      [Presentation]
Demos
algorithms.py

Today we continue our discussion of invariants and algorithms from the previous lecture. We review the Dutch National Flag algorithm and talk about how changing invariants can change your algorithm.

## Week 13

### 16 November (Thursday): Sequence Algorithms

[Handout]      [Presentation]
Demos
algorithms.py

Instead, today we start on the last major topic in the course: sorting. Before we get to sorting, we have start with the framework for building complex algorithms on sequences (strings, lists, etc.). This lecture covers advanced loop-invariants, and is a very important lecture for the final exam.

### Lab 12: Loop Invariants

[Instructions]

This second to last lab gives you a lot of practice with loop-invariants. In particular, it shows you how to use invariants to construct a function with a while-loop. While many of you may be able to skip this lab (because you have done all of the labs so far), we recommend that you do not do this. This is one of the major new topics on the final.

### 14 November (Tuesday): GUI Applications

[Handout]      [Presentation]
Demos
animation.py
arrows.py
state.py
touch.py
subcontroller.py
pyro.py

Today we return to classes one last time, and show how classes and while-loops fit together. By the end of the lecture, we will see that class invariants and loop invariants are really the same thing in practice. Today's lecture will provide you all that you need to know to get started on the last assignment.

## Week 12

### 9 November (Thursday): Loop Invariants

[Handout]      [Presentation]
Demos
pairs.py
invariants.py

Today we discuss how to design algorithms for while-loops. We introduce the notion of a loop-invariant, and show how to use that to write a program with a loop. Invariants are an important topic on the final exam, and are covered in the final labs.

### Lab 11: Loop Exercises

[Instructions]

This is the first of several labs involving loops. It includes while-loops over both ranges integers and over more complicated conditions. Given both the exam and the assignment, we have tried to make this lab reasonable.

### 7 November (Tuesday): While Loops

[Handout]      [Presentation]
Demos
flow.py
comparison.py
numerical.py

Today we introduce while-loops, which are an alternate form of iteration. They are trickier to use than for-loops, and will be an important part of the last part of the course.

## Week 11

### 2 November (Thursday): Programming with Subclasses

[Handout]      [Presentation]
Demos
newfrac.py
raising.py
trying.py

Now that we have subclasses, there is quite a bit we can do with them. To understand how to program with subclasses, we need to understand how to make type more explicit in our programs. We do that in this lecture, including a review of the try-except statement that we saw earlier in the course.

### Lab 10: Subclassing and Encapsulation

[Instructions]

This is a short(ish), but fun, lab that gives you experience with subclasses. In particular, you can see how subclasses can be very useful in graphics applications. We have also added some optional practice functions on nested lists. This topic will be on the next prelim and Fall Break prevented us from using them in a previous lab.

### 31 October (Tuesday): Inheritance

[Handout]      [Presentation]
Demos
employee.py
initialize.py
override.py
resolve.py
app.py

Subclasses and inheritance are integral part of object oriented programming. It allows us to take classes that someone else created (such as the GUI classes that Kivy provides) and add functionality to them. Today we show how these features are used in Python.

## Week 10

### 26 October (Thursday): Operators and Abstraction

[Handout]      [Presentation]
Demos
frac1.py
frac2.py
frac3.py
frac4.py
pixels.py

There is a lot going on with classes in Python. There are all these mysterious methods that start with an underscore. Today we talk these mysterious methods. We show how to use these methods to create classes for mathematical types like fractions or complex numbers. As part of this, we cover the concept of abstraction, which involves hiding unnecessary details from your users.

### Lab 9: Blackjack

[Instructions]

This is a straight-forward lab that gives you some experience working with classes. And when you are done, you can play a nice game of blackjack.

### 24 October (Tuesday): Using Classes Effectively

[Handout]      [Presentation]
Demos
point.py
rect.py
ctime.py
card.py
hand.py
goodtime.py

In previous lectures, we have learned the syntax for defining classes. Today we look at the design philosophy for making classes. This lecture is very similar to Lecture 9 (Algorithm Design), except that it is for classes instead of functions.

## Week 9

### 19 October (Thursday): Classes

[Handout]      [Presentation]
Demos
example.py
example2.py
point.py
worker.py
person.py
testperson.py

Up until now, if we wanted to use objects, we had to import a module that provided them for us. Today we finally learn how to create our own classes. Not only can we make our own class types now, but we can even add them to the Python visualizer.

### Lab 8: Recursion Exercises

[Instructions]

This lab gives you experience with writing recursive functions. All of the functions in this lab are either recursive functions on sequences (e.g. strings or lists), or recursive functions on integers, just as we saw in class.

### 17 October (Tuesday): More on Recursion

[Handout]      [Presentation]
Demos
morefun.py
testmore.py
palindrome.py
testpalindrome.py
person.py
testperson.py
hilbert.py

Today we continue to talk about recursion. We look at the different ways that we can break up a recursive function, and more advanced uses of divide-and-conquer. We also look at how recursion is used in Assignment 4.

## Week 8

### 12 October (Thursday): Recursion

[Handout]      [Presentation]
Demos
factorial.py
fibonacci.py
memory.py
deblank.py
stringfun.py
teststring.py

Today we talk about recursion, a powerful computing tool and one of the harder concepts in the course. Recursion is one of the fundamental principles of computer science, and used for a lot of advanced algorithms. We will see many applications as the course progresses.

### 10 October (Tuesday): FALL BREAK

There is no class today.

## Week 7

### 5 October (Thursday): Nested Lists and Dictionaries

[Handout]      [Presentation]
Demos
matrix.py

This lecture covers several advanced topics on sequences. In particular, we will look at the topic of multi-dimensional lists, and why we would want to use them. We also introduce dictionaries, which are similar to a sequence, but have several important differences.

### Lab 7: Lists & For-Loops

[Instructions]

This lab has you work with lists and write several functions using for-loops. There is no lab the week of Fall Break, so you technically have two weeks to do this lab. However, the material from this lab may be on the exam. Therefore, you may want to complete it as soon as possible.

### 3 October (Tuesday): For-Loops

[Handout]      [Presentation]
Demos
loops.py
iters.py
ranges.py

Lists (and sequences) come with their own special control structure: the for-loop. In this lecture we see what for-loops can (and cannot) do to make more interesting programs.

The material in this lecture is the last material that will be on the first prelim.

Reading: Sections 8.3, 8.7, Chapter 10

## Week 6

### 28 September (Thursday): Lists (and Sequences)

[Handout]      [Presentation]

Now that you are an expert of string slicing, we introduce another sliceable data type: lists. Lists behave just like strings, except that they can contain data other than text. They are also mutable, which means we need to use folders to represent them.

### Lab 6: Asserts & Debugging

[Instructions]

We have talked a lot about errors and debugging in the last few weeks. This week you will get hands-on experience finding errors in some rather complex functions. In addition, you will learn how to add asserts to better stop errors before they appear.

### 26 September (Tuesday): Asserts and Error Handling

[Handout]      [Presentation]
Demos
error.py
anglicize.py
try.py
recover.py

We have talked about how preconditions are a promise that indicate what your function will and will not do. Today we will show how to make them more than a promise. We will also show how error reporting relates to the call stack.

## Week 5

### 21 September (Thursday): Memory in Python

[Handout]      [Presentation]
Demos
globals.py
reorder.py
anglicize.py

Throughout the past few weeks, we have seen several different ways of representing memory in Python. Today we put everything together, introducing global space, heap space, and the call stack. The latter is the collection of frames for all currently executing functions.

### Lab 5: Objects & Conditionals

[Instructions]

Now that you are an expert of writing functions, our labs can include more interesting challenges. In this lab, we show how to use conditionals in functions. Our functions will use strings (just like Assignment 1) as well as a new class called Time.

### 19 September (Tuesday): Objects

[Handout]      [Presentation]
Demos
pfuncs.py

Today, we introduce the notion of objects. Objects are a new type of data. They require a new conceptual model for us to understand them. They will be a major part of Assignment 3.

## Week 4

### 14 September (Thursday): Algorithm Design

[Handout]      [Presentation]
Demos
reorder.py
anglicize.py
testang.py

Your first assignment is very much do-this/do-that. Today we step back and see how we would design a complex program from scratch. How do we take a complex task and break it up into manageable pieces?

### Lab 4: Assignment 1

[Instructions]

In recognition of the looming assignment, today's lab is a chance for you to work on Assignment 1. There are some optional exercises on the lab, in case you need more practice before you start Assignment 1. However, these are not necessary and you will get credit for the lab so long as you turn in Assignment 1 on time Sunday night.

### 12 September (Tuesday): Conditionals and Control Flow

[Handout]      [Presentation]
Demos
name.py
debug_name.py
test2.py
flow.py

Today we talk about the difference between program structure and program flow. We also introduce the conditional, which is our first program structure for controlling program flow. This will not be necessary for Assignment 1, but will be very important in later assignments.

## Week 3

### 7 September (Thursday): Specifications and Testing

[Handout]      [Presentation]
Demos
greet.py
temp.py
name.py
debug_name.py
test1.py
test2.py

We now know how to write some complex functions. However, writing functions takes a lot of practice and you are likely make mistakes along the way. That is why it is extremely important to test your functions and make sure they are working properly. As part of testing, we will also see why comments are more important that just notes to yourself.

### Lab 3: Working with Strings

[Instructions]

This week's lab is the most important one all semester. It covers a lot of important topics that you will need before you can start on the first assignment. In particular, you will learn how to write your own functions and put them into a module.

### 5 September (Tuesday): Strings

[Handout]      [Presentation]
Demos
greet.py
middle.py
pvr.py
commalist.py

Python really shows off its power when working with text. Today we go into depth about the string type, which is how Python represents text. We show how to cut up text and paste it back together. The techniques that we learn will be very important for the first assignment.

## Week 2

### 31 August (Thursday): Defining Functions

[Handout]      [Presentation]
Demos
plusone.py
foo.py
temp.py
globals.py

Now that we know how to use functions, we can learn how to create our own functions. As part of this, we will learn the important difference between a function call and a function definition.

### Lab 2: Functions and Assignments

[Instructions]

The purpose of this lab is to get you comfortable with using functions and modules provided by Python library. It has almost the same format as last-weeks lab. At the end of the lab you will write your first (simple) module.

### 29 August (Tuesday): Functions and Modules

[Handout]      [Presentation]
Demos
module.py
script.py
helloApp.py
plusone.py
temp.py

Today we introduce the concept of a module and show how they provide Python with extra (optional) functionality. We show how to use the many modules built into Python, and how to make our own modules.

## Week 1

### 24 August (Thursday): Variables and Assignments

[Handout]      [Presentation]

While we got started with a little bit of Python last time, this time we will jump into it. We show how to use Python as a calculator, and introduce the notion of expressions and types. We also introduce the notion of a variable, and how an assignment statement works.
We will use the iClickers for the first time today.

### Lab 1: Getting Started

[Instructions]

The purpose of this lab is two fold. First, it is designed to get you started with Python immediately. Second, gives you hands on experience with Python expressions, which we talked about on the first day of class.

### 22 August (Tuesday): Types and Expressions

[Handout]      [Presentation]