What's the difference between a Python list and an array?

In GCSE pseudocode the term is 'array'. In Python you use a list, which is essentially the same thing for GCSE purposes. Python does have an actual array type but it's not needed at this level.

Are Python lists zero-indexed?

Yes. The first item is at index 0. Negative indices count from the end: list[-1] is the last item.

How do I remove an item from a list?

.remove(value) removes the first item equal to value. .pop() removes and returns the last item. .pop(i) removes and returns the item at index i.

Python lists

A list is Python's built-in way to store many values in order, and it appears in every UK GCSE Computer Science specification (called an 'array' in the pseudocode). This unit covers creating lists, indexing (l[0]) and slicing (l[1:4]), the common list methods (.append(), .remove(), .pop(), .insert()), and iterating over a list with for. Every example runs in the browser so learners can watch the list change as items are added and removed. Perfect for classroom teaching, GCSE and A Level revision, and independent or home-schooled learners.

What you'll learn

Create a list with square brackets: scores = [10, 20, 30]
Access items by index: scores[0]
Modify items by assignment: scores[0] = 99
Grow a list with .append(); remove with .remove() or .pop()
Loop over a list with for item in list
Use len(list) to count items

UK GCSE topic coverage

Lists (arrays)
List indexing
List length
List mutation
for over items
for + index
List methods (`.append()`)
Functions that take/return lists
Sequences and mutability
Applied lists

Worked example

Build a list of scores and print the highest

scores = []
for _ in range(3):
    scores.append(int(input("Score? ")))
print("Highest:", max(scores))

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Lessons in this unit

Full interactive lessons with checked tasks are available to signed-in RunPy users. Unit 1 and a selection of exam-style questions are free with a RunPy account.

What is a list?
Accessing list items
Negative indexing and boundaries
List length with len()
Updating list items
Iterating over a list with for
Iterating with index using range() and len()
Building lists with .append()
Using functions with lists
Lists and strings: comparing the two
Composite list challenge

Frequently asked questions

What's the difference between a Python list and an array?: In GCSE pseudocode the term is 'array'. In Python you use a list, which is essentially the same thing for GCSE purposes. Python does have an actual array type but it's not needed at this level.
Are Python lists zero-indexed?: Yes. The first item is at index 0. Negative indices count from the end: list[-1] is the last item.
How do I remove an item from a list?: .remove(value) removes the first item equal to value. .pop() removes and returns the last item. .pop(i) removes and returns the item at index i.