Feel free to take a look at this tutorial in advance, but since attendance is required this first week so you can meet your team, you do not need to actually work on it until class on Wednesday.

Submitting

Regardless of how you choose to complete the assignment, you MUST submit the file you worked on to Canvas.

In future weeks you will be allowed to submit remotely and have your .py file checked for correctness. That isn’t an option this first week.

If you’re submitting in-class, make sure to check-in (there will be one question called CHECK-IN Q only available for the first 7 minutes of class) and check-out (there will be a three question survey called CHECKOUT SURVEY only available for the last 10 minutes of class) using PollEverywhere with your location verified.

Getting Started

Our objectives for this assignment are:

1. Storing data in variables
2. Doing basic math in Python
3. Understanding data types
4. Calling basic functions

Part 0. Meet Your Group

A first step to building any community is to introduce yourselves!

Once in your group, figure out who has the earliest birthday (i.e. January 1st is the earliest possible birthday). This person will go first and introduce themselves with the following:

• Name
• Major
• Year in School
• Favorite Breakfast Cereal (or other delightful breakfast delicacy)

Note, your group will have a Peer Mentor or TA assigned to it and they will come introduce themselves as well! They’ll be easy to identify as they’ll all have name tags! Because PMs are assigned to multiple groups, they may not be present for all the intros and might ask you to quickly go around and say names again.

Once you’ve all had a chance to introduce yourselves, you can get started on your tutorial!

Part 1. Get Your Files Organized

Create the folder organizational structure recommended in class during Monday’s Lecture.

cs110
    |-- homeworks
    │   |-- hw0
    │   |-- hw1
    |   ...
    |-- lectures
    |   -- lecture00
    │   -- lecture01
    │   -- lecture02
    │   ...
    |-- tutorials
        ...

Part 2. Create two Python files and Write Some Programs

When you’re done, open IDLE and create a new python file (go to File menu > “New File”). This should open a blank document. Then save this blank document as grade_calculator.py (File menu > “Save as…”), and put it inside of your cs110 > tutorials > tutorial1 folder (You’ll need to make that tutorial1 folder just like you did with the three top-level folders).

In this newly created grade_calculator.py file, you’re going to write a program to calculate your grade in our class:

Storing Data in Variables

1. First create a new variable called miniquizzes and store in it the number 100 (see hint below).
2. Next, create a new variable called projects and store in it the number 95.
3. Next, create a new variable called exercises and store in it the number 95.
4. Next, create a new variable called tutorials and store in it the number 100.
5. Finally, create a new variable called quizzes and store in it the number 90.

Make sure to run your program by going to the Run menu at the top of the screen and selecting Run Module.... If you don’t see any red error text, that means your program successfully ran! Since we haven’t asked Python to actually output anything yet (we’ve only asked it to remember some numbers) we won’t see any output.

Accessing Data in Variables

Accessing data stored in a variable is as easy as using the name of the variable in another line of our program. Python will then see this name and lookup what value you’ve asked it to remember is stored inside that container.

Assuming we got 100s in every assignment category our Grade Calculation Equation would be…

(0.10 * 100) + (0.05 * 100) + (0.25 * 100) + (0.25 * 100) + (0.35 * 100)

But we want to make a calculator for any grade combination so let’s use our earlier variables. For example, the overall tutorial score is scored in the variable tutorials so we replace (0.10 * 100) in the above program with (0.10 * tutorials).

Action Items

1. Use this example to modify the Grade Calculation Equation above so that is uses the variables you created earlier rather than values of 100.
2. Store the result of this calculation in a variable called grade
3. Run your program! (if you run into an error (i.e. red text or a popup saying it can’t run) raise your hand to ask for help!)
4. print the value stored in grade!

Using the input Function

At this point we’ve asked the computer to remember the average of our scores across these 5 different types of assignments and then calculate the resulting course average. These variables are currently “set in stone” or hardcoded to be particular numbers. Every time we run this program, it will always use those exact same numbers for the calculation. While that’s fine when calculating our grade, what if we wanted to be able to send our program to a friend in the class so they could calculate their grade without modifying the code?

Using the input function, we can tell Python to ask the person running the program to type a number using keyboard. The input function takes a string as an argument which represents the prompt Python shows the user and returns a string of whatever the person typed in (after they type it in and hit enter on the Interpreter Window).

Action Items

1. Modify the quizzes variable so that instead of being assigned the value of 90, it is instead assigned the value of running the input function (see hint below).
2. Now try running your program, making sure to type a number in the Interpreter/Shell Window and then hit the return key on your keyboard.

Dealing with Errors

Did it work? No? Uh oh. Let’s think about why by using the error we got as a clue:

Traceback (most recent call last):
  File "/Users/username/Desktop/tutorial1/grade_calculator.py", line 7, in <module>
    grade = (0.10 * tutorials) + (0.05 * miniquizzes) + (0.25 * homeworks) + (0.25 * projects) + (0.35 * quizzes)
TypeError: can't multiply sequence by non-int of type 'float'

Action Items

1. To convert the quizzes variable to an integer we need to use the int function which accepts any argument and will try its best to return an int (integer) from that argument.
   • There’s two (easy) ways you can implement this in your program.
   • You could add a new line after the line that says quizzes = ... that says quizzes = int(quizzes). This tells Python to replace the existing quizzes variable with the result of converting whatever is currently in the quizzes variable to an int.
   • You could change the calculation of grade to use int(quizzes) rather than just quizzes. This tells Python to not modify the original variable but to instead just convert the value for the purposes of the calculation.
2. Pick one of these approaches and implement it in your program
3. Run your program! Make sure to try different numeric inputs to see you get different final grades!

Part 3. Turtle Time

This time, rather than starting from scratch, we’re going to give you a template to work in. Click the big purple button below to download the file turtorial.py. Move that downloaded file into your tutorial1 folder and go ahead and open it in IDLE.

Tutorial Starter File

### TURTLE CHEATSHEET ###############################################
# Pretend we have a turtle named: turtle_0

# If we want turtle_0 to go forward 100 steps we just say:
forward(turtle_0, 100)

# If we want turtle_0 to turn left or right 90 degrees, we just say:
left_turn(turtle_0, 90)
right_turn(turtle_0, 90)

# If we want to turn turtle_0 around, we'd just turn 180 degrees!
right_turn(turtle_0, 180)

# If we want turtle_0 to change the color of its pen:
change_pen_color(turtle_0, "green")

# If we want to make a new turtle at a specific x, y coordinate, we use the optional

# arguments to the MyTurtle Function like so

turtle_0 = MyTurtle(x = 100, y = 100)
# (If you leave those out, it will default to 0, 0)

Action Items

1. Modify the program so that your turtle draws a square.
2. Modify the program so that after drawing a square the turtle…
   • first changes its pen color to "cyan"
   • then draws a rectangle (i.e. a shape with non-equal sides)
3. Finally, depending on how much time is left, make a SUPER COOL design. What sorts of shapes are easy to draw? What sorts of shapes are difficult to draw?

Some Pro Tips

• Always save your python file before running it so that the interpreter “sees” your changes.
• In order for your interpreter to recognize your file as a Python file, you must give it the .py file extension (e.g. my_program.py).
• Don’t forget to name all of your variables “snake case” (all lower case, underscores to separate words).
• If your code doesn’t run, practice reading and trying to understand what the interpreter is telling you. If you see red error text, the computer is trying to tell you where the problem is.