Checkpoint 17.8.1.
Run the code to see what it draws.
Section 17.8 Creating Functions with Turtles
Learning Objectives:
- Create functions that take a turtle object and draw a shape
- Add parameters to make functions more reusable
- Use
begin_fillandend_fillto fill a shape - Use
bgcoloron the screen to change the background color of the screen object.
Here is code that draws a square with a turtle using a
for loop with range.We can create a function out of the code that draws the square.
- Keep the import at the top of the code
- Move the code that draws the square after the import
- Add a function definition and pass in a turtle object. You can call it anything, but
turtleis a good name for an object of theTurtleclass. - Modify the code in the function to use the local name (
turtle). - Add a call to the function after you create the
turtleand pass in theturtleobject. Use whatever name you gave the turtle when you created it.
When we execute
square(alisha) the local variable turtle is set to the same object as alisha. Notice that we still need to import the library, create the screen object, create the turtle object, and call the function.Checkpoint 17.8.2.
Run the code to see what it draws.
We can change the
square function to take a length to make it more reusable. We can change the length when we call the function to draw different squares. We can even set a default value for length in case a value isn't specified for it.Checkpoint 17.8.3.
Run the code to see what it draws.
Let's practice creating reusable functions from code that draws a shape with a
turtle object.Checkpoint 17.8.4.
Run the code first to see what it draws and then modify it to create a
triangle function and pass in the length of each side. Then draw several triangles with the function.We can add even more parameters to set the fill color. We can make the default fill color green. Use
begin_fill() to start the shape you want to fill and end_fill() after the shape is finished.Checkpoint 17.8.5.
Run the code to see what it draws.
You can change the size of the screen object, set a background color for the screen, and set the code to not exit until you click the window. You need to do this when you run turtle code outside of the ebook otherwise the program will run but exit before you can even see the result.
Checkpoint 17.8.6.
Run the code to see what it draws.
Checkpoint 17.8.7.
Add a function to draw an equilateral triangle and then write a function to draw a simple house by calling the functions to draw a triangle and a square.
