2D arrays and lists
Lesson details
Learning outcome
I can define and use two-dimensional lists.
Key learning points
- A list is used to hold multiple elements under one name.
- A two-dimensional list allows you to hold a list as one element.
- Data in a 2D list can be held in rows and columns.
Keywords
List - a dynamic data structure that can contain items of different data types
Two-dimensional - describes a list or array that has both columns and rows of values
Array - a static data structure that contains items of the same data type
Common misconception
Arrays and lists behave in the same way.
An array has a predefined fixed size. A list can vary in size throughout program execution.
Teacher tip
Indexing in 2D lists can be difficult for pupils to understand. Perhaps draw a table with index values in a grid so students can become familiar with the indexing of the rows and columns.
Equipment
Pupils will need access to a device that can edit and run Python programs. Examples in this lesson use the RPF Code Editor https://oak.link/python-editor
Licence
Lesson video
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Prior knowledge starter quiz
6 Questions
Q1.What does this code do?
123animals = ["dog", "cat", "rabbit"]
animals.insert(1, "hamster")
print(animals)Code colour
Q2.What will be the output of the following code?
12colors = ["red", "blue", "green", "blue"]
print(colors.count("blue"))Code colour
Q3.Which method would you use to add an item to the end of a list?
Q4.What does the pop() method do in a Python list?
Q5. What is the correct way to remove "apple" from the following list?
1fruits = ["banana", "apple", "cherry"]Code colour
Q6.A can return multiple values by placing them in a list.
Assessment exit quiz
6 Questions
Q1.What is a two-dimensional (2D) list?
Q2.How do you access the value at row index 1 and column index 2 in the following 2D list?
1234grades = [
["Math", "Science", "History"],
[85, 90, 78]
]Code colour
Q3.Which of the following correctly defines a 2D list in Python?
Q4.What will be the output of the following code?
12345table = [
["apple", "banana", "cherry"],
[3, 2, 5]
]
print(table[0][1])Code colour
Q5.The () method can be used to add a new row to a 2D list.
Q6.How can you change the value "dog" to "cat" in the following 2D list?
1234animals = [
["lion", "tiger", "dog"],
["parrot", "eagle", "owl"]
]Code colour
To help you plan your 10 computer science lesson on: 2D arrays and lists, download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your 10 computer science lesson on: 2D arrays and lists, download all teaching resources for free and adapt to suit your pupils' needs.
The starter quiz will activate and check your pupils' prior knowledge, with versions available both with and without answers in PDF format.
We use learning cycles to break down learning into key concepts or ideas linked to the learning outcome. Each learning cycle features explanations with checks for understanding and practice tasks with feedback. All of this is found in our slide decks, ready for you to download and edit. The practice tasks are also available as printable worksheets and some lessons have additional materials with extra material you might need for teaching the lesson.
The assessment exit quiz will test your pupils' understanding of the key learning points.
Our video is a tool for planning, showing how other teachers might teach the lesson, offering helpful tips, modelled explanations and inspiration for your own delivery in the classroom. Plus, you can set it as homework or revision for pupils and keep their learning on track by sharing an online pupil version of this lesson.
Explore more key stage 4 computer science lessons from the Programming: strings and lists unit, dive into the full secondary computer science curriculum, or learn more about lesson planning.