Fiducia TogetherArrays and lists
A single name holding many values, reached by position.
Please note: This page explains a word or a process in education. It is general information about the system, the law and the guidance in England — not advice about your child, your school or your exam. If a decision is going against you, get advice from one of the free services we link to before you agree to anything or miss a deadline. If you are revising, check your own exam board's specification: boards word things differently and yours is the one that marks you.
What it is
An array is an ordered collection of items of the same type, accessed by index. In most languages indexing starts at 0. A list in Python is similar but can grow and hold mixed types. A two-dimensional array is an array of arrays — a grid.
Where it applies
GCSE and A Level computer science.
How it works
Arrays let a loop process many values with one piece of code, which is the whole reason they exist.
A record or struct groups values of DIFFERENT types under one name, which is the other half of data structures at this level.
How to use it in your work
Watch the starting index. Off-by-one errors from assuming index 1 are the single most common array mistake.
For 2D arrays, be consistent about whether the first index is the row or the column, and say which.
When looping through an array, use its length rather than a hard-coded number.
Where to get help
Your teacher and your board's specification — the pseudocode and the required language differ between boards. Bitesize covers the concepts; the computer science song runs the topics.
Revise this with a song
These are ours. We write revision songs because a lot of people remember a tune when they cannot remember a page, and because revising out loud in the kitchen beats staring at a highlighter.
- The Computer Science Song The GCSE computer science topics, set to music.
Where to read more
Last reviewed 2026-08-28 by Fiducia Together · Next review due 2027-08-28
Please note: This page explains a word or a process in education. It is general information about the system, the law and the guidance in England — not advice about your child, your school or your exam. If a decision is going against you, get advice from one of the free services we link to before you agree to anything or miss a deadline. If you are revising, check your own exam board's specification: boards word things differently and yours is the one that marks you.