All words

Every word of Yu: how to write it, what it does and an example. This chapter is built from the language core, so it is never out of date.

Basics

say · скажи

say(…)

Prints what is in the brackets in the terminal. Several values separated by commas become one line with spaces between them.

say("Hello, world!")
say("2 + 2 =", 2 + 2)

Hello, world!
2 + 2 = 4

ask · запитай

ask(question)

Shows a question and waits for the person to type an answer. The answer is always text; wrap it in number(…) to get a number.

Yurii

name = ask("What is your name?")
say("Hi, " + name + "!")

Hi, Yurii!

text · текст

text(x)

Turns a value into text. That way you can, for example, count the digits of a number.

year = 2026
say("The number", year, "has", length(text(year)), "digits")

The number 2026 has 4 digits

number · число

number(x)

Turns text into a number you can calculate with. A decimal point or a comma both work.

price = number("12.5")
say("Two of them cost", price * 2)

Two of them cost 25

round · округли

round(x)

Rounds a number to the nearest whole number: 2.4 becomes 2 and 2.5 becomes 3.

average = (7 + 8 + 10) / 3
say("Average mark:", round(average))

Average mark: 8

random · випадкове

random(a, b)

Gives a random whole number from a to b, both ends included. It is different every time.

dice = random(1, 6)
say("The dice shows", dice)

The dice shows 4

Conditions

if · якщо

if condition:

Runs the block below it only when the condition is true. The block is the lines indented by four spaces.

temperature = 25
if temperature > 20:
    say("It is warm today")

It is warm today

else · інакше

else: · else if condition:

Comes after if. The block under else runs when the condition is false, and else if checks one more condition.

score = 7
if score >= 10:
    say("Excellent")
else if score >= 6:
    say("Good")
else:
    say("Try again")

Good

and · or · not · і · або · не

a and b · a or b · not a

Combine conditions. “and” is true when both parts are true, “or” when at least one is, and “not” turns true into false and back.

age = 12
if age > 6 and age < 18:
    say("Goes to school")
if age < 6 or age > 65:
    say("Does not go to school")
say("Grown up:", not (age < 18))

Goes to school
Grown up: false

true · false · так · ні

true · false

The two truth values. Comparisons give them, and if and while use them to decide what to do.

sun = true
rain = false
say("Sun:", sun, "Rain:", rain)
say("5 > 3:", 5 > 3)

Sun: true Rain: false
5 > 3: true

nothing · нічого

nothing

Means there is no value. A function without return gives it back.

found = nothing
say("Found:", found)

Found: nothing

Loops

repeat … times · повтори … разів

repeat N times:

Repeats the block N times. The word times after the number may be left out.

stars = ""
repeat 5 times:
    stars = stars + "*"
say(stars)

*****

while · поки

while condition:

Repeats the block while the condition is true. Make sure the condition turns false at some point, or the loop never ends.

money = 10
while money >= 3:
    money = money - 3
    say("Bought an ice cream,", money, "left")

Bought an ice cream, 7 left
Bought an ice cream, 4 left
Bought an ice cream, 1 left

for … from … to · для … від … до

for i from A to B step S:

Counts from A to B, both ends included, and runs the block for each number. The step may be left out; then it is 1.

for i from 1 to 3:
    say(i, "× 2 =", i * 2)
for i from 0 to 20 step 10:
    say(i)

1 × 2 = 2
2 × 2 = 4
3 × 2 = 6
0
10
20

for … in · для … у

for x in list:

Goes through a list one item at a time: each time x is the next item.

for fruit in ["apple", "pear", "plum"]:
    say("In the basket:", fruit)

In the basket: apple
In the basket: pear
In the basket: plum

break · стоп

break

Leaves the loop at once, even if it has not finished.

for i from 1 to 10:
    if i == 4:
        break
    say(i)

1
2
3

continue · далі

continue

Skips the rest of the block and goes straight to the next round of the loop.

for i from 1 to 6:
    if i % 2 == 0:
        continue
    say(i, "is odd")

1 is odd
3 is odd
5 is odd

Functions

function · функція

function name(parameters):

Gives a block a name so you can call it again and again. The brackets hold the parameters: values the function gets when it is called.

function greet(name):
    say("Hi, " + name)

greet("Olya")
greet("Taras")

Hi, Olya
Hi, Taras

return · поверни

return value

Ends the function and hands a value back to where it was called.

function square(n):
    return n * n

say("5 squared:", square(5))

5 squared: 25

Lists

length · довжина

length(x)

How many items a list has, or how many characters a text has.

friends = ["Olya", "Taras", "Marko"]
say("Friends:", length(friends))
say("Letters in Kyiv:", length("Kyiv"))

Friends: 3
Letters in Kyiv: 4

append · додай

append(list, x)

Adds a value to the end of a list. Items are numbered from 1: list[1] is the first.

shopping = ["bread"]
append(shopping, "milk")
say(shopping)
say("Second:", shopping[2])

["bread", "milk"]
Second: milk

Drawing

canvas · полотно

canvas(w, h)

Changes the size of the canvas in pixels. It starts at 600 by 400; call canvas at the very beginning of the program.

canvas(300, 300)
background("lightblue")
color("yellow")
circle(150, 150, 100)

background · фон

background("colour")

Paints the whole canvas one colour. Write the colour's name in quotes.

background("blue")
color("yellow")
rect(0, 200, 600, 200)

color · колір

color("colour")

Sets the colour of the next shapes, lines and labels. A colour name, "#ff8800" or "random" all work.

color("red")
circle(200, 200, 80)
color("#ff8800")
circle(400, 200, 80)

thickness · товщина

thickness(n)

Sets the width of lines in pixels, both for line and for the turtle.

thickness(2)
line(100, 150, 500, 150)
thickness(12)
line(100, 250, 500, 250)

circle · коло

circle(x, y, r)

Draws a filled circle: x and y are the centre, r is the distance from the centre to the edge.

color("red")
circle(300, 200, 80)

rect · прямокутник

rect(x, y, w, h)

Draws a filled rectangle: x and y are the top left corner, then the width and the height.

color("brown")
rect(200, 150, 200, 150)
color("red")
rect(270, 220, 60, 80)

line · лінія

line(x1, y1, x2, y2)

Draws a straight line from the point x1, y1 to the point x2, y2.

color("green")
thickness(6)
line(100, 300, 300, 100)
line(300, 100, 500, 300)

label · напис

label(text, x, y)

Writes text on the canvas; x and y are the top left corner of the text.

color("blue")
label("Hello from Yu", 220, 190)

Turtle

forward · вперед

forward(n)

The turtle walks n pixels ahead and draws a line while the pen is down. It starts in the centre, facing right.

color("blue")
forward(150)

back · назад

back(n)

The turtle walks n pixels backwards without turning around.

forward(100)
back(200)

right · праворуч

right(°)

The turtle turns right, clockwise, by that many degrees.

repeat 4 times:
    forward(120)
    right(90)

left · ліворуч

left(°)

The turtle turns left, anticlockwise, by that many degrees.

repeat 3 times:
    forward(150)
    left(120)

pen_up · підніми_перо

pen_up()

The turtle keeps walking but stops drawing until you put the pen down.

forward(60)
pen_up()
forward(40)
pen_down()
forward(60)

pen_down · опусти_перо

pen_down()

The turtle draws again as it walks. At the start the pen is already down.

pen_up()
back(200)
pen_down()
forward(400)

begin_fill · почни_заливку

begin_fill()

Starts recording the turtle's path so the shape inside can be filled later.

color("yellow")
begin_fill()
repeat 5 times:
    forward(200)
    right(144)
end_fill()

end_fill · заверши_заливку

end_fill()

Fills the shape the turtle walked around since begin_fill with the current colour.

color("green")
begin_fill()
repeat 3 times:
    forward(160)
    left(120)
end_fill()

Colours

Write a colour name in quotes. Ukrainian names in any gender form, English names, "#ff8800" and "random" all work.