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TASK 1

Variables

It is often really useful to keep the value of something for later use when you are programming. For example, it would be really annoying if websites asked for your login and password every time you went to a new page!

To solve this problem, we can remember values in code by assigning them to variables

A variable is like a box, you can put the value into the box, and later on when you want that value again, you can just get it out of the box.

Since you might end up with lots of boxes, we put labels on the boxes, called identifiers.

The identifier is the name of your variable, and your variable holds a value.

Don't worry, if that sounds a little complicated, here is an example!

x : int = 10

Okay, so here we used the identifier x for a variable, which holds an int.

This tells the computer to get an int shaped box ready, and put the label x on the front.

Do you have any idea what the code print(x) might output?

Remeber, x is the variable, not a string!

Close this box and find out if you are right!

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GUIDE

This guide is intended to help with syntax. See the prelude section for pre-defined functions and variables. See the tutorials page for tutorials on how to write code.

• Data Types

  • int

    int

    Integer values, such as 2, -4 and 254.

  • float

    float

    Floating point values, such as 2.0, -4.72 and 254.2681.

  • string

    string

    String values, such as "hello, world!", "haha" and "33".

  • boolean

    boolean

    Boolean values True and False.

  • colour

    colour

    Colour values for drawing on the canvase, See the prelude for more.

  • list

    list[element_type]

    List values. Note the element type must be correctly specified. Examples are [1,2,3], [["hello"], ["world"]] and [].

• Variables

  • declaration

    name: type

    A variable must first be declared with a type before it can be used

  • assignment

    name = value

  • increment

    name += value

    Only applicable to integer values. Equivalent to name = name + value .

  • decrement

    name -= value

    Only applicable to integer values. Equivalent to name = name - value .

• Expressions

  • logic

    Applicable to boolean values. and, or and not.

  • mathematical

    Applicable to numerical values. +, -, *, **, /, // and %.

  • relational

    Applicable to comparable values. >, <, ==, !=, <= and >=.

• Selection Statements

  • if

    if condition: statements elif condition: statements else: statements

• Loops

  • while

    while condition: statements

  • for

    for ident in list: statements

• Function

  • function

    def name(parameter: parameter_type) -> return_type: statements

    Values can be returned with return

  • procedure

    def name(parameter: parameter_type): statements

    Equivalent to a function which returns a None type

Can't find what you're looking for?

Check the tutorials page for more!

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PRELUDE

The prelude is all the pre-defined functions and variables available to use. See the tutorials page for tutorials on how to write code.

• Terminal Functions

  • print

    print(expr)

    Prints the value of the expression to the terminal.

  • print_str

    print_str(expr)

    Prints the value of the expression as a string to the terminal.

  • clear_terminal

    clear_terminal()

    Clears the terminal.

  • input

    input(message: str) -> str

    Displays message to the user, and returns their input as a string.

• Type Functions

  • str

    str(expr) -> str

    Where possible returns the string representation of expr.

  • int

    int(expr) -> int

    Where possible parses the integer representation of expr.

  • float

    float(expr) -> float

    Where possible parses the float representation of expr.

  • len

    len(expr) -> int

    Where possible returns the length of expr.

  • type

    type(expr) -> str

    Returns the name of the type of expr.

• Math Functions

  • round

    round(n: float) -> int

    Rounds the value of n using bankers rounding.

  • random_int

    random_int(from: int, to: int) -> int

    Returns a random integer between from and to.

  • random_float

    random_float(from: float, to: float) -> float

    Returns a random float between from and to.

  • pi

    pi: int

    The value of π.

• String Functions

  • upper

    str.upper()

    Returns the uppercase of str.

  • lower

    str.lower()

    Returns the lowercase of str.

  • replace

    str.replace(s1: str, s2: str)

    Returns a string will all occurances of s1 replaced with s2.

  • split

    str.split(d: str)

    Returns a list of strings of str split on all occurances of d.

  • join

    str.join(ss: list[str])

    Returns a string from joining all strings in ss using d.

  • isnumeric

    str.isnumeric() -> bool

    Returns true if all characters in str are numbers.

• List Functions

  • append

    l.append(elem)

    Appends elem to the list l.

  • remove

    l.remove(elem)

    Removes the first instance of elem from the list l.

  • count

    l.count(elem)

    Returns the total of elems present in the list l.

  • range

    range(f: int, t: int) -> list[int]

    Returns the list of values from f to t.

• Drawing Functions

  • line

    line(x1: int, y1: int, x2: int, y2: int)

    Draws a line from (x1,y1) to (x2,y2).

  • rect

    rect(x: int, y: int, w: int, h: int)

    Draws a rectangle of dimensions w by h on the canvas at position (x,y).

  • circle

    circle(x: int, y: int, r: int)

    Draws a circle with radius r on the canvas at position (x,y).

  • ellipse

    ellipse(x: int, y: int, r1: int, r2: int)

    Draws an ellispe with horizontal radius r1 and vertical radius r2 at position (x,y).

  • arc

    arc(x: int, y: int, r: int, f: int, t: int)

    Draws an arc with radius r on the canvas at position (x,y) from f degrees to t degrees.

  • sect

    sect(x: int, y: int, r: int, f: int, t: int)

    Draws a sector with radius r on the canvas at position (x,y) from f degrees to t degrees.

  • triangle

    triangle(x1: int, y1: int, x2: int, y2: int, x3: int, y3: int)

    Draws a triangle with corners at positions (x1,y1), (x2,y2) and (x3,y3).

  • polygon

    polygon(xs: list[int], ys: list[int])

    Draws a polygon with corners at positions (xi,yi) from xs and ys.

  • img

    img(x: int, y: int, w: int, h: int url: string)

    Draws the image loaded from the url at position (x,y) with width w and height h.

  • text

    text(x: int, y: int, t: string)

    Draws the text t at position (x,y).

• Colour Functions

  • rbg

    rgb(r: int, g: int, b: int) -> colour

    Returns the colour for the respecive red, green and blue values.

  • rbga

    rgba(r: int, g: int, b: int, a: float) -> colour

    Returns the colour for the respecive red, green and blue and alpha values. Alpha is opacity, in the range 0.0 to 1.0.

  • red

    red: colour

    The built in colour red, equivalent to rgb(240, 51, 51).

  • green

    green: colour

    The built in colour green, equivalent to rgb(98, 203, 166).

  • blue

    blue: colour

    The built in colour blue, equivalent to rgb(117, 117, 232).

  • pink

    pink: colour

    The built in colour pink, equivalent to rgb(197, 89, 146).

  • yellow

    yellow: colour

    The built in colour yellow, equivalent to rgb(221, 192, 107).

  • white

    white: colour

    The built in colour white, equivalent to rgb(255, 255, 255).

  • black

    black: colour

    The built in colour black, equivalent to rgb(0, 0, 0).

  • transparent

    transparent: colour

    The built in colour transparent, equivalent to rgba(0, 0, 0, 0.0).

• Canvas Functions

  • width

    width: int

    The width of the canvas in pixels.

  • height

    height: int

    The height of the canvas in pixels.

  • line_colour

    line_colour(c: colour)

    Sets the canvas line colour to c.

  • fill_colour

    fill_colour(c: colour)

    Sets the canvas fill colour to c.

  • line_width

    line_width(w: int)

    Sets the canvas line width to w.

  • font_size

    font_size(s: int)

    Sets the canvas font size to s.

  • translate

    translate(x: int, y: int)

    Translates the canvas by (x,y).

  • rotate

    rotate(a: int)

    Rotates the canvas by angle a in degrees.

  • scale

    scale(x: float, y: float)

    Scales the canvas size by (x,y).

  • frame_rate

    frame_rate(s: int)

    Sets the frame rate of the definable draw function.

  • stop_draw

    stop_draw(s: int)

    Stops the execution of the definable draw function.

• Definable Functions

  • draw

    def draw():

    Is called at frame_rate, intended for animations and games on the canvas.

  • left_pressed

    def left_pressed():

    Is called whenever the left arrow key is pressed.

  • right_pressed

    def right_pressed():

    Is called whenever the right arrow key is pressed.

  • up_pressed

    def up_pressed():

    Is called whenever the up arrow key is pressed.

  • down_pressed

    def down_pressed():

    Is called whenever the down arrow key is pressed.

  • space_pressed

    def space_pressed():

    Is called whenever the space key is pressed.

Can't find what you're looking for?

Check the tutorials page for more!