2D arrays and lists
I can define and use two-dimensional lists.
2D arrays and lists
I can define and use two-dimensional lists.
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Lesson details
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.
To help you plan your year 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 year 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.
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The assessment exit quiz will test your pupils' understanding of the key learning points.
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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.
Equipment
All pupils require access to devices that can edit and run Python programs. Starter code files are available to copy or use directly via the Raspberry Pi Code 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 colourWhen programmers write code, they use a special tool called an IDE (Integrated Development Environment). In an IDE, different colours are used to help programmers understand the code:
- • Blue - numbers and boolean values
- • Green - strings
- • Purple - keywords
When programmers write code, they use a special tool called an IDE (Integrated Development Environment). In an IDE, different colours are used to help programmers understand the code:
- • Blue - numbers and boolean values
- • Green - strings
- • Purple - keywords
Q2.What will be the output of the following code?
12colors = ["red", "blue", "green", "blue"]
print(colors.count("blue"))Code colourWhen programmers write code, they use a special tool called an IDE (Integrated Development Environment). In an IDE, different colours are used to help programmers understand the code:
- • Blue - numbers and boolean values
- • Green - strings
- • Purple - keywords
When programmers write code, they use a special tool called an IDE (Integrated Development Environment). In an IDE, different colours are used to help programmers understand the code:
- • Blue - numbers and boolean values
- • Green - strings
- • Purple - keywords
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 colourWhen programmers write code, they use a special tool called an IDE (Integrated Development Environment). In an IDE, different colours are used to help programmers understand the code:
- • Blue - numbers and boolean values
- • Green - strings
- • Purple - keywords
When programmers write code, they use a special tool called an IDE (Integrated Development Environment). In an IDE, different colours are used to help programmers understand the code:
- • Blue - numbers and boolean values
- • Green - strings
- • Purple - keywords
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 colourWhen programmers write code, they use a special tool called an IDE (Integrated Development Environment). In an IDE, different colours are used to help programmers understand the code:
- • Blue - numbers and boolean values
- • Green - strings
- • Purple - keywords
When programmers write code, they use a special tool called an IDE (Integrated Development Environment). In an IDE, different colours are used to help programmers understand the code:
- • Blue - numbers and boolean values
- • Green - strings
- • Purple - keywords
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 colourWhen programmers write code, they use a special tool called an IDE (Integrated Development Environment). In an IDE, different colours are used to help programmers understand the code:
- • Blue - numbers and boolean values
- • Green - strings
- • Purple - keywords
When programmers write code, they use a special tool called an IDE (Integrated Development Environment). In an IDE, different colours are used to help programmers understand the code:
- • Blue - numbers and boolean values
- • Green - strings
- • Purple - keywords
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 colourWhen programmers write code, they use a special tool called an IDE (Integrated Development Environment). In an IDE, different colours are used to help programmers understand the code:
- • Blue - numbers and boolean values
- • Green - strings
- • Purple - keywords
When programmers write code, they use a special tool called an IDE (Integrated Development Environment). In an IDE, different colours are used to help programmers understand the code:
- • Blue - numbers and boolean values
- • Green - strings
- • Purple - keywords