← Teacher guide Markdown for Prepare

A quiz app: cheat sheet

Apps with Gradio · In any playground, open Reference to copy these.

square (loop)

Draw a square by repeating forward and right four times.

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

running total

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

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

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)
What it draws
A square spiral: each line longer than the last

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)
What it draws
One line per colour in the list

class

A new kind of object. __init__ runs when one is made; self.name = value stores a value in that object.

class Star:
    def __init__(self, x):
        self.speed = 5

s = Star(100)

a quiz question

A question as a dictionary, and a Radio input made from it: the student picks one of the choices, and the function gets that text.

{"q": "What is 7 x 8?", "choices": ["54", "56", "64"], "answer": "56"}

inputs.append(gr.Radio(q["choices"], label=q["q"]))

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()
What it draws
range(5): five dashes

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)
What it draws
Red and blue sides, taking turns

str

Turn a number into text, so it can be joined: "Score: " + str(score).

str(score)

dictionary value

The value stored under that key. The key goes in quotes. Assign to it to change it: star["speed"] = 8.

star["speed"]

method

A function inside a class. Call it on one object: star.move(). self is that object.

    def move(self):
        self.turtle.forward(self.speed)

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