Creating Variables - Week 07

Welcome to week 7 of Intro to Web Dev!

Now you know how to use p5.js to write code and call functions to draw on the screen, and you know how to use variables like width and height. (And if you were feeling spicy last week, you also learned about user input with variables like mouseX and mouseY!)

This week, you’ll learn how to create your own variables to store information.

Work through the activities in this page to complete the week!

Creating Variables

First, read through this tutorial to learn about creating your own variables:

Optional Extra Spicy Bonus Content 🔥

This section is not required!! But if you’re comfortable with the idea of creating your own variables, and you want to take it to the next level, read this to learn about using your variables to create animations:


Now you know how to create your own variables. You’ve also seen a little bit of randomness!

To practice that, create a p5.js sketch that creates your own variables.

If it helps, here are a couple code-alongs for how I would approach the project:

This code-along creates a sketch from an abstract shape:

This code-along creates a sketch from randomly generated cats:

Your sketch must run without any errors. Your sketch must contain at least ten variables that you create using the let keyword and then use either as function parameters or to calculate the value of another variable.

For example:

function setup() {
  createCanvas(400, 400);

function draw() {

  let pointOneX = random(width);
  let pointOneY = random(height);
  let pointTwoX = random(width);
  let pointTwoY = random(height);
  let midPointX = (pointOneX + pointTwoX) / 2;
  let midPointY = (pointOneY + pointTwoY) / 2;

  line(pointOneX, pointOneY, pointTwoX, pointTwoY);
  circle(midPointX, midPointY, 25);

This code creates 6 variables that it uses to draw a circle on the midpoint of a random line. (So for full credit, you’d need to add 4 more.) Using randomness is optional! The important piece is that you’re practicing using variables by creating and using 10 variables.

If you want an extra spicy bonus challenge, try adding animation to your sketch!