1.4 - Matrices
(Two-Dimensional Arrays)

Have you heard of The Matrix ? If you haven't watched it, you should.

Two-dimensional arrays of data are also known as a matrix. They can be written in several ways but most people think of them like a typical x-y plane of rows and columns.

Games, grids, and data science use matrices to control, manipulate, and calculate large amounts of data. Whenever you see a shape drawn on a computer, there is a good chance the data for that visualization is being held in a matrix.

A matrix is always listed as height first, then width. So a m x n matrix has height m and width n.

• A QR Code is a good example of using a 2D Matrix (array) to visualize data. Here's a QR Code Generator to see it in action. And here's a description of the complicated algorithm that generates QR's.

• A path or maze from a start point to an end is another good example.

• An extension to a path is a heat map. A heat map is a path that shows different colours based on how many times a particular point is hit.

• We can also store numbers based on place-value and search much faster this way.

• Think about checkers, chess, minesweeper, connect-four, battleship...

Some important resources: 