Introduction to Computer Science using Python


  • Final Exam, 15th December 7pm Sci 101

Class Info

Section 1: MWF 9:30–10:20, Sci Cntr 240
Professor: Andrew Danner
Office: Sci 247
Office hours: by appointment

Other Sections: Jeff Knerr (MWF 11:30am–12:20pm) | Jason Waterman (TR 9:55am–11:10pm)

Welcome to CS21. This course will introduce fundamental ideas in computer science while also teaching you how to write computer programs. We will study algorithms for solving problems and implement solutions in the Python programming language. Python is an interpreted language that is known for its ease of use. We also introduce object-oriented programming and data structures. A deeper coverage of these topics will be presented in CS 35.

This course is appropriate for all students who want to learn how to write computer programs and think like computer scientists. It is the usual first course for computer science majors and minors. Students with advanced placement credit or extensive programming experience should place out of this course and instead begin with CS 33 or CS 35.

Required Textbook:

Goals for the course:

By the end of the course, we hope that you will have developed the following skills:

Student Support

CS21 Ninjas are student mentors who will assist me in class and run evening study sessions in the main CS lab.
The CS21 Ninjas (student mentors) are: Jake Weiner, Katherine Hamilton, Justin Cosentino, Molly Feldman, Jocelyn Adams, and Cynthia Ma.

Study sessions

You are invited -- and encouraged -- to participate in Ninja evening study sessions to prepare for quizzes, to discuss programming concepts, and to get friendly assistance in working on lab assignments. Our CS mentoring team is dedicated to helping students, who have no prior knowledge of computer science, learn to program in Python while keeping their senses of humor intact. As an added bonus, free food will be provided at the sessions. The sessions are held:

Weekly Evening Ninja Sessions
Sundays 7-9pm Sci Center 240
Wednesdays 7-9pm Sci Center 240

Lab Sessions

The CS lab is open 24 hours a day, 7 days a week for you to use for CS21 lab assignments. In addition, the CS21 professors will be in the CS labs at the times listed below to help CS21 students with lab assignments. You are not required to attend any of these sessions, but you should take advantage of them to get assistance with your lab assignments. Any CS21 student is welcome to attend any/all session.

Weekly Lab Sessions
1:30-3:00 Mondays Danner Science Center 240
2:30-4:00 Mondays Waterman Science Center 240
2:00-3:30 Fridays Knerr Science Center 240

Accessing the CS labs after hours

You can use your ID to gain access to the computer labs at nights and on the weekends. Just wave your ID over the microprox reader next to the lab doors. When the green light goes on, just push on the door handle to get in (the door knob will not turn). If the green light doesn't go on, then we need to enter your microprox number into the system. email if you have problems with this. If the building is locked, you can use your ID to enter the door between Martin and Cornell library. For this class, your ID will give you access to the labs in rooms 238 and 240.

How to Succeed in CS 21

Academic Accommodations

If you believe that you need accommodations for a disability, please contact Leslie Hempling in the Office of Student Disability Services, located in Parrish 130, or e-mail lhempli1 to set up an appointment to discuss your needs and the process for requesting accommodations. Leslie Hempling is responsible for reviewing and approving disability-related accommodation requests and, as appropriate, she will issue students with documented disabilities an Accommodation Authorization Letter. Since accommodations may require early planning and are not retroactive, please contact her as soon as possible. For details about the Student Disabilities Service and the accomodations process, visit the Disability Services webpage.

To receive an accommodation for a course activity, you must have an Accomodation Authorization letter from Leslie Hempling and you need to meet with me to work out the details of your accommodation at least one week prior to the activity.

You are also welcome to contact me privately to discuss your academic needs. However, all disability-related accommodations must be arranged through Leslie Hempling in the Office Of Student Disability Services.


Grades will be weighted as follows:
40%Lab assignments
25%Final Exam
05%Class Participation

Quiz policy

Quizzes will be given at the beginning of class on the days posted in the Announcements section of the Schedule. Please look over these dates carefully and contact the professor in advance if you cannot be in class for a quiz.

If you are not present at the start of class on the day of a quiz, but make it to class before the end, then you may take the quiz. Otherwise you will receive a zero for that quiz.

Lab policy

Lab assignments will typically be assigned in class at the beginning of the week and will be due before midnight the following Tuesday night. You are strongly encouraged to start early and to attend the study sessions for extra practice.

You will submit you assignments electronically using the handin21 program. You may submit your assignment multiple times, but each submission overwrites the previous one and only the final submission will be graded.

Late assignments will only be accepted if you contact the professor at least a day before the deadline with a legitimate reason for needing extra time, such as an illness or needing to leave campus.

Even if you do not fully complete an assignment, you should submit what you have done to receive partial credit.

Programming Style

Programming is not a dry mechanical process, but a form of art. Well written code has an aesthetic appeal while poor form can make other programmers and instructors cringe. Programming assignments will be graded based on style and correctness. Good programming practices usually include many of the following principles:

Also, look over the Python Code Style Guide for more details and some examples of good code style.

Academic Integrity

Academic honesty is required in all work you submit to be graded. You may not submit work done with (or by) someone else, or examine or use work done by others to complete your own work. Your code should never be shared with anyone; you may not examine or use code belonging to someone else, nor may you let anyone else look at or make a copy of your code. This includes sharing solutions after the due date of the assignment.

All code you submit must be your own with the following permissible exceptions: code distributed in class, code found in the course text book, and code worked on with an assigned partner. In these cases, you should always include detailed comments that indicates on which parts of the assignment you received help, and what your sources were.

Discussing ideas and approaches to problems with others on a general level is fine (in fact, we encourage you to discuss general strategies with each other), but you should never read anyone else's code or let anyone else read your code. You may discuss assignment specifications and requirements with others in the class to be sure you understand the problem. In addition, you are allowed to work with others to help learn the course material. However, with the exception of your lab partner, you may not work with others on your assignments in any capacity.

``It is the opinion of the faculty that for an intentional first offense, failure in the course is normally appropriate. Suspension for a semester or deprivation of the degree in that year may also be appropriate when warranted by the seriousness of the offense.'' - Student Handbook (2010-2011, pg20 Section A.3.b.i)

Please see me if there are any questions about what is permissible.


This is a tentative schedule; it may change as we go.
1 Sep 03   Introduction to Python and Unix
Chapt. 1-2
In class
Lab 00
Lab 01
Sep 05  
Sep 07  
2 Sep 10   Numbers and Strings
Chapt. 3-4 (Skip 4.6)
In Class
Lab 02
Sep 12  
Sep 14 Drop/add ends
Quiz 1 Topics
3 Sep 17   Booleans
Chapt. 7.1, 7.2, 7.3 and 8.4.1 p. 246-247
In Class
Lab 03
Sep 19  
Sep 21  
4 Sep 24   Graphics, objects
Chapt. 5 (skip 5.5, 5.6)
notes on the Graphics Library
Lab 04
Sep 26  
Sep 28 Quiz 2 Topics
5 Oct 01 Final Exam Schedule Functions, objects
Chapt. 6 (skip 6.3)
In class
Lab 05
Oct 03  
Oct 05  
6 Oct 08   Loops, More Functions
Chapt. 8.1, 8.2, 8.3
In class
Lab 06
Oct 10  
Oct 12 Quiz 3 Topics

Oct 15

Fall Break

Oct 17

Oct 19

7 Oct 22   Top Down Design, File I/O
Chapt. 9.1, 9.2, 9.3, 4.6 In class
Lab 07
Oct 24  
Oct 26  
8 Oct 29   More Top Down Design, File I/O
Chapt. 9.1, 9.2, 9.3, 4.6
Oct 31  
Nov 02 Quiz 4 Topics
9 Nov 05   Searching, Analysis of Algorithms
Chapt. 13.1
Lab 08
Nov 07  
Nov 09 CR/NC/W Deadline
10 Nov 12   Sorting, Analysis of Algorithms
Chapt. 13.2, 13.3
Lab 09
Nov 14  
Nov 16 Quiz 5 Topics
11 Nov 19   Recursion
Chapt. 13.1-13.3
Lab 10
Nov 21  

Nov 23


12 Nov 26   Defining new classes and Linked Lists
Chapt. 10.1, 10.3, 10.4
Lab 11
Nov 28  
Nov 30  
13 Dec 03   Linked lists Lab 12
Dec 05  
Dec 07 Quiz 6 Topics
14 Dec 10   Wrap up

Dec 15

Final Exam 7pm-10pm Sci101

Links that are related to the course may be posted here. If you have suggestions for links, let me know.

Vi Quick Reference
Python style guide From Prof. Tia Newhall
Using Unix Improved
Basic Unix Commands
Python Documentation
Zelle Textbook site