# 4.4. Turtle Procedures¶

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

Turtle procedures

Name

Input

Description

backward

amount

Moves the turtle backward by the specified amount. If the pen is down, draws a line. A move of 0 makes a dot if the pen is down.

forward

amount

Moves the turtle forward by the specified amount. If the pen is down, draws a line. A move of 0 makes a dot if the pen is down.

goto

x, y

Moves the turtle to position x, y. Note you must put a comma between the two values.

left

angle

Turns the turtle counter clockwise by the specified angle

right

angle

Turns the turtle clockwise by the specified angle

angle

Turns the turtle to face the given heading. East is 0, north is 90, west is 180, and south is 270.

speed

number

How fast to move the turtle. Should be a value from 1-10 (1 is slow, 10 is fast), or 0 which means “as fast as possible”.

xcor

None

A function - returns the current x position of the turtle.

ycor

None

A function - returns the current y position of the turtle.

hideturtle

None

Hides the turtle (the triangle icon)

pendown

None

Puts down the turtle’s pen so that it draws when it moves

penup

None

Picks up the turtle’s pen so that it doesn’t draw when it moves

pensize

width

Sets the width of the pen for drawing

color

colorname

Sets the color for drawing. Use strings - like ‘red’, ‘black’, etc… This page has a table of colors Make sure to put quotation marks around the name of the color!

begin_fill

None

Tells the turtle to start painting inside the shape it draws

end_fill

None

Tells the turtle to stop painting inside the shape it draws

fillcolor

colorname

stamp

None

Stamps a copy of the turtle’s icon at the current location.

shape

shapeName

Changes the icon used to represent the turtle. shapeName should be set to one of the following: “arrow”, “turtle”, “circle”, “square”, “triangle”, “classic”.

Note

You can find this table easily by look for “turtle - procedure list” in the book index.

To draw more than one letter you can use the penup() procedure after drawing the first letter to pick up the pen before moving to where you want to start the next letter. Once you are ready to draw again, use pendown(). The example below draws a C and an S.

Note

In the sample we use blank lines to break up the code into logical chunks and comments to describe what each chunk does. The computer does not care about these things, but these tricks make it much easier for humans to understand what is happening.

Try some experiments on the code:

• Change the speed to a different value (1-10)

• Try looking up some other colors and change what color the turtle draws with.

• Try commenting out the code in the section called # Draw the S to see how the turtle is repositioned after the C so it can start the S.