Working with the Turtle

A computer program is just a series of instructions given to a computer to perform. Here is an example of a program in Python that uses the turtle module.

import turtle

# Creating a turtle object as defined in the turtle module imported above

tina = turtle.Turtle()

# Turtle objects have associated functions that either set properties of the turtle or move the turtle.
# Here we set three turtle properties

tina.shape('turtle')
tina.width(2)
tina.color('blue')

# Definition of the square() function
# Instructs the turtle how to draw a square

def square():
  tina.forward(100)
  tina.right(90)
  tina.forward(100)
  tina.right(90)
  tina.forward(100)
  tina.right(90)
  tina.forward(100)
  tina.right(90)

square()

Notes:

• To use the turtle module it must first be imported as done on the first line using the import command.
• All lines beginning with # are comments. These are not read by the Python interpreter.
• All instructions are performed line by line from top to bottom
• The variable tina is an example of an object (of type Turtle). The turtle module provides different properties that can be set for turtle objects. For example: shape, width, and color. Notice the use of the dot (operator) when assigning these properties. The turtle module also provides different methods/actions that the turtle can perform. For example: forward, and right. Again, notice the use of the dot when implementing these methods.
• The line def square() gives a name to our sequence of instructions that move the turtle. In order to run these instructions, we must type square() ... this is called a function in Python. The line def square() simply defines the function, whereas the line square() actually runs the instructions contained within the function.