TASK 4

Names

You might have been wondering, what happens if two variables have the same name?

It's simple, they can't!

Within one block of code, every variable must have a unique identifier

In the next piece of code, you'll see that we attempted to create two variables called x.

You can name variables absolutely anything, within a few rules:

Your task is just to rename one of these variables so that the code can run!

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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



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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.



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Check the tutorials page for more!