Python Foundations with Turtle: cheat sheet

Python Foundations with Turtle · In any playground, open Reference to copy these.

Commands, loops and values

forward

Move the turtle forward. The number is how many steps.

forward(100)

right

Turn clockwise by this many degrees.

right(90)

Example

forward(60)
right(90)
forward(60)

penup

Lift the pen so moving does not draw.

penup()

Example

forward(40)
penup()
forward(40)
pendown()
forward(40)

speed

How fast the turtle moves, from 1 (slow) to 10 (fast).

speed(10)

for loop

Repeat the indented lines this many times.

for i in range(4):
    pass

Example

for i in range(5):
    forward(15)
    penup()
    forward(10)
    pendown()

variable

Give a value a name, so you can reuse and change it.

size = 50

Example

length = 120
forward(length)
left(90)
forward(length / 2)

named turn

Name the number of sides once; the turn is worked out from it.

sides = 5
for i in range(sides):
    forward(60)
    right(360 / sides)

Example

sides = 6
for i in range(sides):
    forward(60)
    right(360 / sides)

grow value

Change a value every pass: read the old one, store a new one.

size = 5
for i in range(20):
    forward(size)
    right(90)
    size = size + 5

Example

size = 5
for i in range(30):
    forward(size)
    right(90)
    size = size + 5

backward

Move the turtle backward without turning.

backward(100)

left

Turn anticlockwise by this many degrees.

left(90)

Example

forward(60)
left(90)
forward(60)

pendown

Put the pen down so moving draws again.

pendown()

Example

forward(40)
penup()
forward(40)
pendown()
forward(40)

square (loop)

Draw a square by repeating forward and right four times.

for i in range(4):
    forward(100)
    right(90)

running total

Start the total at 0 once, then add to it on every pass.

total = 0
while total < 10:
    total += int(input("Add: "))

every other

i % 2 == 0 is true on every second pass.

for i in range(8):
    if i % 2 == 0:
        pass
    else:
        pass

Example

for i in range(8):
    if i % 2 == 0:
        pencolor("red")
    else:
        pencolor("blue")
    pensize(6)
    forward(30)
    right(45)

Red and blue sides, taking turns

counter step

Use the counter i to make each pass different.

for i in range(20):
    forward(i * 5)
    right(90)

Example

for i in range(30):
    forward(i * 5)
    right(90)

print

Show text or a value in the output box.

print("Hello")

Choices and lists

goto

Jump to a position. (0, 0) is the centre; x goes right, y goes up.

goto(0, 0)

Example

goto(80, 60)

From the centre to (80, 60)

pencolor

Set the line colour, using a colour name.

pencolor("red")

Example

pencolor("red")
forward(100)

begin_fill / end_fill

Everything drawn between these two lines is filled in.

begin_fill()

end_fill()

Example

fillcolor("orange")
begin_fill()
for i in range(4):
    forward(60)
    right(90)
end_fill()

list

Keep many values in order under one name. The first item is place 0.

colours = ["red", "blue", "green"]

for each item

Work through a list, one item at a time.

for c in colours:
    pass

Example

pensize(6)
for c in ["red", "blue", "green"]:
    pencolor(c)
    forward(40)

pensize

Set how thick the line is.

pensize(5)

Example

pensize(1)
forward(50)
pensize(8)
forward(50)

fillcolor

Choose the colour to fill shapes with.

fillcolor("blue")

Example

fillcolor("blue")
begin_fill()
circle(40)
end_fill()

if / else

Do one thing or the other, depending on a condition.

if x > 0:
    pass
else:
    pass

Example

for x in [-90, -30, 30, 90]:
    penup()
    goto(x, 0)
    if x > 0:
        dot(30, "red")
    else:
        dot(30, "blue")
hideturtle()

in

True if the item is in the list (or the key is in the dictionary, or the letters are in the text).

if item in bag:
    pass