Storage and data organisation - Eduqas1D and 2D arrays

Arrays

An array is a data structure that allows a programmer to organise data into groups of similar data. All the data in an array must be the same data type.

One-dimensional arrays

Take, for example, a list of employees in an organisation. These could be stored in an array called 'Employees' with the data typestring.

Each employee in the organisation class can be identified by their position in the array, which is called an index. Computers tend to count from 0, so in the example above ‘Ivan Weber’ is 0, ‘Sue Thompkins’ is 1, and so on. This would be referenced in a program or pseudocode using the name of the array, in this case 'Employees', with the index in square brackets.

Employees [0] = ‘Ivan Weber’

Employees [1] = ‘Sue Thompkins’

Two-dimensional arrays

Where the manager needs to store more data about each employee they may use a two-dimensional array, which can be described as a matrix with rows and columns. This allows each piece of data to be divided into separate categories. Instead of storing only the name of each employee they may store their first name and surname separately, along with their staff number and postcode. All the data in a two-dimensional array has to be the same data type, in this example ‘string’.

Employees

This would be referenced in a program or pseudocode using square brackets to represent the row and then the column.

The postcode of Akansha Shar can be found in 'Employees' [2,3].

Two-dimensional arrays are often used to process pixel colour data of bitmap images.