Arrays

Lesson Objectives

To understand what an array is and it’s function

To know how code and array in VB

The Basics

So we know what a variable is and how it can store one piece of information at one time, bit like a box

You can insert something into the box.

‘name’

You can find out whats in the box by referencing

The Problem

The downside to this is that you have to declare lots of variable if you want to store lots of information

To the rescue

There’s a way to get round this, and that’s arrays

An array in its simplest form is a variable that has lots of slots in which you can store information, a bit like pigeonholes

So the whole thing is an array with the slots being areas in which you can use

How does it work in VB

So just like variables you have to declare the array and also specify the type of the array

Dim myArray(10) As String

Assigning to the array

myArray(0) = ‘Hello’

Referencing the array

myVar = myArray(0)

Don’t forget that the

indexes start at o (zero)

This means that if you set up an array with 5 slots the first

one is accessed using myArray(0)

The number of slots you need

Multidimensional Arrays

There are times in which it would be useful to sort more information, for example storing information about a set of people.

0 1 2 3 4 5 6

Single-Dimensional Array

0, 0 1, 0 2, 0 3, 0 4, 0 5, 0 6, 0

0, 1 1, 1 2, 1 3, 1 4, 1 5, 1 6, 1

0, 2 1, 2 2, 2 3, 2 4, 2 5, 2 6, 2

0, 3 1, 3 2, 3 3, 3 4, 3 5, 3 6, 3

0, 4 1, 4 2, 4 3, 4 4, 4 5, 4 6, 4

Multi-Dimensional ArrayFirst Dimension

Second Dimension

Multidimensional Arrays

Dim myArray(3, 2) As Integer

Assigning to the array

myArray(0, 1) = 132

Referencing the array

myVar = myArray(0, 0)

The same principles apply to a multidimensional array as they do to a single-dimension array

Tom James Pete John

132 40 75 83

4 3 4 5

Challenges

Bronze Challenge - Copy this program, to create and display a list of names. Each name should be printed to a new line.

Silver Challenge - Create a multi-dimensional array to store the name and star sign of a group of students. Display a details for a random person when the program is run.

Gold Challenge - Use a multi-dimensional array to store names & scores for these Strictly Come Dancing results.