Variables, Constants & Assignments (Edexcel GCSE Computer Science)
Revision Note
Written by: James Woodhouse
Reviewed by: Lucy Kirkham
Variables, Constants & Assignments
What is a variable?
A variable is a named memory location that holds data that during the execution of a program, the data can change
Variables can store a variety of different types of data such as numbers, text or true/false values
To store data in a variable, the process of assignment is used
What is a constant?
A constant is fixed data that during the execution of a program cannot change
A constant can store a variety of different types of data, similar to variables
Pi is an example of a mathematical fixed value that would typically be stored as a constant
What is assignment?
Assignment is the process of storing data in a variable or constant under a descriptive name
Assignment is performed using the '=' symbol
Assigning variables & constants
Concept | Python |
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Data Types
What is a data type?
A data type is a classification of data into groups according to the kind of data they represent
Computers use different data types to represent different types of data in a program
The basic data types include:
Data type | Used for | Example |
|---|---|---|
Integer | Whole numbers | 10, -5, 0 |
Real | Numbers with a fractional part | 3.14, -2.5, 0.0 |
Character | Single character | 'a', 'B', '6', '£' |
String | Sequence of characters | "Hello world", "ABC", "@#!%" |
Boolean | True or false values | True, False |
It is important to choose the correct data type for a given situation to ensure accuracy and efficiency in the program
Data types can be changed within a program, this is called casting
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