Fall 2026
Schedule
Readings, practice problems, programs, and quizzes, week by week.
The slides and handouts for CS 230. Start with the welcome guide to install Python and VS Code, then follow the lectures in order.
Getting Started
The schedule, setting up your computer, and turning in your work.
Setup
Welcome
Install Python 3.14 and VS Code, then run your first program.
Submitting
Code in Brightspace
Paste code into a Brightspace text box with Insert Code so it keeps its indentation.
Lectures
Introduction to Python
What a program is, where Python is used, and running Python from the terminal and from VS Code.
Variables and Statements
Variables, comments, input, the int,
float, and str types, and
input-process-output programs.
Booleans and If Statements
Comparisons, and and or,
if/elif/else, and
match.
While Loops
Repeating with while, infinite loops,
break, continue, and nested loops.
For Loops
Counting with for and range, choosing
between while and for, and nested loops.
Strings and Format Strings
Indexing, slicing, len, in, string
methods like split and join, and
f-strings.
Functions
Defining functions, parameters, return,
None, local variables, and optional parameters.
Lists
Creating and indexing lists, append, looping over a
list, and min, max, and
sum.
Changing Lists
Slicing, insert, remove,
pop, copying a list, sorted and
sort, tables as lists of lists, and tuples.
Exceptions and Files
try and except, reading a file with
with open, splitting lines into fields, and writing
with print(..., file=out).
The os Module
import os, building paths with
os.path.join, the current working directory, listing
a folder with os.listdir, and checking paths with
os.path.isfile and os.path.exists.
Dictionaries
Creating dictionaries, looking up keys with in and
KeyError, looping with keys,
values, and items, and counting with a
dictionary.
Records and Sets
del and update, dictionaries of
dictionaries and of lists, sets and |,
&, and -, and hashable keys.
Web Apps with Streamlit
A live demo that builds a tip calculator and a map of this
week's earthquakes: widgets like st.slider, reruns,
math with st.latex, layout with columns and the
sidebar, and maps, charts, and tables.
Tables with pandas
Series and DataFrames, read_csv, selecting and
filtering rows, new columns, sorting, groupby, and
to_csv.
Handouts
Extra reading that goes with the lectures.
String Cheat Sheet
Everything about strings from Chapter 8 of the textbook and class, in one place.
Changing Lists Cheat Sheet
Slicing, adding and removing items, copies, sorting, tables, and tuples, from Chapter 6 of the textbook and class.
Exceptions and Files Cheat Sheet
try and except, and reading and writing
files, from Chapter 7 of the textbook and class.
The os Module Cheat Sheet
The current working directory, paths, listing and checking files, and textbook programs K-1 and K-2, from Appendix K of the textbook and class.
Dictionaries and Sets Cheat Sheet
Looking up, counting, records, dictionaries of lists, sets, and set operations, from Chapter 9 of the textbook and class.
Data Files
Every file the lectures read, to look at or download, and where to save each one.
Patterns
Short pieces of code that solve problems that come up often: Look Before You Leap and Easier to Ask for Forgiveness than Permission.
In progress
Why Python Has with
Why a file has to be closed even when something goes wrong, how
finally did that before with, and what
else with cleans up.
How a Python Program Exits
Stopping a program early with sys.exit, why
exit() belongs to the interactive shell, and what the
exit status tells other programs.
Week 4
Practice Problem 1 Walkthrough
Breaking the date-validation problem into a loop and small checks.