Turtle Functions and Procedures

Learning Objectives:

• Introduce more turtle functions and procedures.

• Show examples using conditionals with turtles.

• Use the modulo operator to detect odd and even

• Show how to generate random numbers in Python

• Use conditionals to avoid a collision

Turtles can do more than go forward, turn left, and turn right. The table below lists turtle functions and procedures.

Name	Parameters	Description
backward	amount	Moves the turle backward by the specified amount
color	colorname	Sets the color for drawing. Use ‘red’, ‘black’, etc
forward	amount	Moves the turtle forward by the specified amount
goto	x,y	Moves the turtle to position x,y
left	angle	Turns the turtle counter clockwise by the specified angle
pendown	None	Puts down the turtles tail so that it draws when it moves
penup	None	Picks up the turtles tail so that it doesn’t draw when it moves
pensize	width	Sets the width of the pen for drawing
right	angle	Turns the turtle clockwise by the specified angle
setheading	angle	Turns the turtle to face the given heading. East is 0, north is 90, west is 180, and south is 270.
shape	shapename	Should be ‘arrow’, ‘classic’, ‘turtle’, or ‘circle’
stamp	None	Leaves an impression of a turtle shape at the current location
Turtle	None	Creates and returns a new turtle object
xcor	None	Returns the x value of the turtle’s position
ycor	None	Returns the y values of the turtle’s position

csp-14-1-1: What procedure would you use to change the size of the line the turtle leaves when it moves?

• shape
• Use shape to set the shape used for the turtle. It doesn't affect the line that is drawn.
• xcor
• Use this function to get the x value of the turtle's position
• pensize
• This changes the width of the line that the turtle draws as it moves.
• color
• Use color to change the line color and the turtle color.

csp-14-1-2: What procedure would you use move the turtle to a given x and y position?

• stamp
• Use stamp to leave a copy of turtle shape at the current position.
• xcor
• Use xcor to get the x value of the turtle's position.
• penup
• Use penup to pick up the pen (stop drawing as you move).
• goto
• Use goto to move to the given x and y position.

Once you are comfortable with the basics of turtle graphics you can read about even more options on the Python Docs Website.

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