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Exercise 2 - Edit a Python Program

You are smarter than the computer. You can think for yourself and do what you want. A computer must be told what to do by a person. Follow the instructions to edit a Python program to tell the computer what you want to draw.

1. Open a Python Program in Thonny and Rename the File

  • Open Thonny if not already open.
  • From the File menu, select Open, go to the Turtle folder in your personal folder.
  • Select the edit file. Click Open.
  • Look at the first line of code. It imports the Turtle library of commands:
🐍 Python Script
from turtle import *

2. Edit the Title of the Window

  • Find the code that defines the title:
🐍 Python Script
title("Edit a Python Script")
  • Click on the green play button to run your code.
  • Look at the top of the canvas. It has the title:

title

  • In the code, add your name to the title
  • From the File menu, select Save or press CTRL + S.
  • Click on the green play button to run your code.
  • Look at the top of the canvas. It has the edited title.

3. Set the Screen Size and Background Color

  • The screen size sets the width and height of the canvas. Change the canvas size:
🐍 Python Script
screensize(1000, 1000)
  • Run your code.
  • Drag the scroll bars to see more of the window.
  • You can set the background color using a color name. Pick a color from the list below:

colors

For example, if we choose honeydew:

🐍 Python Script
bgcolor(“honeydew”)
  • Check the changes.

4. Change the Speed, Pen Size, and Shape of the Turtle

  • The speed that the Turtle moves can be changed. Try it!

speed

  • The pen size can be set. A low value makes a thin line. A higher value makes a thick line. Change the pen size to a number between 1-10.
  • The Turtle can be many shapes. Pick one you like:

shape

  • Check the changes.

5. Move the Turtle to Draw a Line

The black line on the canvas is made using this code:

🐍 Python Script
#move turtle
pencolor("black")
forward(100)
right(30)
backward(130)
left(90)
forward(20)
  • Edit the amount the Turtle moves forward and backward to change the line.
  • Edit the angle the Turtle moves right and left. Pick a number between 0-360:

6. Edit the Location and Size of a Circle

The blue circle on the canvas is made using this code:

🐍 Python Script
#draw a circle
penup()
goto(100, 100)
fillcolor("blue")
begin_fill()
circle(25)
end_fill()
  • You can tell the Turtle to go to a specific point on the canvas. Tell it to go to the top right of the canvas (400, 400)
  • You can set the width of a circle. Change the size.

7. Customize a Loop to Draw a New Shape

A loop is a block of instructions that are done more than once. A square has four lines. A loop is used to draw each line:

🐍 Python Script
#draw a rectangle using a loop
penup()
goto(-100, 50)
setheading(90)
pencolor ("green")
pendown()
# beginning of the loop
for line in range(4):
    forward(30)
    right(90)
# end of the loop
  • Edit the number of times the code loops and change the angle to create a new shape.

8. Write a Message

Text is added to the canvas using write:

🐍 Python Script
#write a message
penup()
goto(-100, -100)
write("Programming is fun!", font=("Arial", 12))
  • Edit the message and the font size.

9. Hide the Turtle to See When a Command is Run"

Python code is linear. Each line runs one instruction at a time from top to bottom.

  • Add hideturtle() after a comment line.
  • Run the program to see when the Turtle is hidden from view. If things happen too fast, slow it down: speed("slowest")
  • Move hideturtle(). Put it after a different comment line. Run the program again.