Iterating through data structures
Lesson details
Learning outcome
I can use iteration to repeatedly add items to lists and check the contents of a string.
Key learning points
- Condition-controlled iteration is implemented using while loops in Python.
- A string is like a list in structure but is immutable, so elements cannot be changed, added or removed.
- Some operations that can be performed on lists can also be performed on strings.
Keywords
Iteration - the process of repeating a sequence of instructions within a program loop
String - a sequence of characters, e.g. letters, numbers, spaces, and other symbols
Mutable - able to be changed
Immutable - not able to be changed
Common misconception
Strings are mutable meaning that any character within the string can be changed.
Strings are immutable. The elements of a string cannot be changed. If changes to the string are required, the whole string must be rewritten.
Teacher tip
A string can be referenced using an index value. Break apart on a whiteboard how the characters of a string are referenced starting with the first character at index 0 and then every subsequent character with the next index value.
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
Loading...
Prior knowledge starter quiz
6 Questions
Q1.What is the correct syntax in Python to initialise a variable called age and set its value to the numerical value 13?
Q2.What is the correct syntax in Python to initialise a variable called name and set its value to Laura?
Q3.Which programming construct is used to repeatedly perform actions in a program?
Q4. are used to tell a program whether a condition has been met or not.
Q5.A while loop will run ...
Q6.12colours = ["red", "blue", "yellow", "green"]
print (colours[1])
What colour would be printed by the program?Code colour
Assessment exit quiz
6 Questions
Q1.A is a data type that is a collection of characters.
Q2.Lists are , which means that their contents can be modified, without having to create a new list.
Q3.Which code would check the first character of name1 does not appear anywhere in name2?
Q4.Which of the following statements about strings is true?
Q5.What code would you use if you wanted to check the value of the first letter held in the string: message = "Hello"?
Q6.If you update the value held by a string, the previous value is .
To help you plan your 9 computing lesson on: Iterating through data structures, download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your 9 computing lesson on: Iterating through data structures, 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 3 computing lessons from the Python programming with sequences of data unit, dive into the full secondary computing curriculum, or learn more about lesson planning.