In this lesson, we will be drawing with the turtle module.
Run Python in interactive mode (write Python in the command line).
$ python >>>
$ are printed by the computer, not by you.
On Windows, it will be
> instead of
>, there can be some other words.
from turtle import forward forward(50)
Now a popup window will appear, don't close it. Place it somewhere where you will be able to see it and your command line, too.
If you are a Mac OS X user and have problems with errors like:
ModuleNotFoundError: No module named '_tkinter'
then TKInter was not yet installed on your system
You will need to install it manually by adding following command in your terminal:
brew install python-tk@3.(your python version)
you can check your version by command python3 --version (it should be for example 3.11.3)
so the first command should be for example: brew install firstname.lastname@example.org
Currently, the turtle is disguised as an arrow. There is a way how to unmask it:
from turtle import shape shape('turtle')
The turtle can rotate and crawl across the "paper". It has a brush on its tail which draws a line.
from turtle import left, right forward(50) left(60) forward(50) right(60) forward(50)
Now give the turtle some commands.
If you don't like the drawing you can close
the window, or import and use the function
Interactive mode is good for trying new stuff but we will now go back to our editors and write some program in a file.
Create a file
~/pyladies can have a different name on your laptop
– see Python installation.
You can have a different name for your file, just don't use
Write drawing commands into the file
and in the end call the function
(imported from module
What does the function
After you are done, we can start with drawing pictures:
If you are using directly the VS Code terminal for running turtle,
instead of using
turtle.done() to "start the main program"
as the last command of your turtle script.
Draw a square.
A square has 4 equal straight sides and 4 90° angles.
Draw a rectangle.
Try to make it so that the turtle will "look" to the right in the end (like it was in the beginning).
Now draw three sqares, each rotated by 20°.
So much code! There has to be a way how to simplify it.
Now we will learn the command
What does the following code do?
Save it as
for number in range(5): print(number) for greeting in 'Ahoj', 'Hello', 'Hola', 'Hei', 'SYN': print(greeting + '!')
What does the command
What does the following program do?
sum = 0 for number in 8, 45, 9, 21: sum = sum + number print(sum)
Back to drawing! This time we will use loops.
Draw a square.
forward only twice, once in the import
and once as function.
pendown from the
module tell the turtle to stop/start drawing.
Try to draw a discontinuous line.
Now try to make it so that the lines that are drawn become gradually bigger.
What exactly does the command
Can we use the variable that it sets up?
Loop variable Naming
Always use a meaningful loop variable name, like for index_tab_browser in range(3, 18): close_tab_in_browser(index_tab_browser) not just i, j, x, y etc. When using meaningful names:
There is one exception - when it's a single-level loop and the variable has no meaning other than "the number of times I've been through this loop", in which case
i can be used.
Finally, draw 3 squares, each rotated by 20°.
Now you know how to write it in a simple way: repeat the code
for, do not copy the code.
When you are done, try to draw stairs:
When you are also done with the stairs, try to draw 7 hexagons: