Data Types

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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

Integers are whole numbers.
- E.g. 12
- E.g. 0
- E.g. -142

Float

Floats are fractional numbers.
- E.g. 0.42
- E.g. 1.00

String

Strings are text data.
- E.g. "Hello, world!"
- E.g. "07123 456 789"

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.

Type Coercion

Type coercion allows us to operate on data of different types.

Type coercion

Usually, attempting to use data of different types in an operation (e.g. adding two numbers of different types) will cause an error.
Type coercion allows one of the types to be automatically cast so that the operation can be completed.

Integers and floats

When working with a float and an integer, the final result will become a float.
- E.g: 3 + 2.5 = 5.5

Strings and integers

When working with a string and an integer, the final result will become a string.
- E.g: "Number = " + 3 = "Number = 3"

1Introduction to Python

1.1Python

1.1.1Python

1.2Input & Output

1.2.1Input & Output

1.3Data Types

1.3.1Data Types

1.4Variables & Constants

1.4.1Variables & Constants

1.5Operators

1.5.1Arithmetic & Relational Operators

1.5.2Boolean & Assignment Operators 2

1.6Program Flow

1.6.1Selection

1.6.2Iteration

2Data Structures

2.1Lists & Strings

2.1.1Lists

2.1.2Strings

2.2File Handling

2.2.1File Handling

3Modularity

3.1Subroutines

3.1.1Subroutines

3.2Data Flow

3.2.1Data Flow

4Good Practice

4.1Naming & Whitespace

4.1.1Identifiers

4.1.2Whitespace

4.2Comments

4.2.1Comments

4.3Exceptions

4.3.1Exceptions

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