Data Types
Computer Science: KS3, topic 2.1.12
Data Types
Every piece of data that is stored has a type. The type determines how it is stored and what you can do with the data.
Integer
- Whole numbers.
- Examples:
- 12, 0, -142.
Float / Real
- Fractional numbers.
- Examples:
- 0.42, 1.00.
String
- Text data.
- Example:
- "Hello, world!".
Character
- A single letter of text data.
- Example:
- 'a'.
Boolean
- A True or False value.
- Examples:
- True.
- False.
Casting
Casting is the process of converting data from one type to another.
Reasons for casting
- One of the most common reasons for casting is output.
- Output must be formatted as a string, and so we may need to convert a certain piece of data to a string.
- All input also comes as a string, and must then be converted to other data types.
Casting functions
- Casting to a string can be done using the str function. E.g:
- str(3) gives "3".
- Casting to an integer can be done using the int function. E.g:
- int(3.4) gives 3.
- Casting to a float can be done using the float function. E.g:
- float("3.4") gives 3.4.
Test yourself on Data Types
What would be the most suitable type to store the number 2.5?
Which of these data are characters?
Which would be the most appropriate type to store a username?
What is one of the most common reasons for casting?