Data Types

The four basic types of value, and how to check them.

Every value in Python has a type. The type tells you what you can do with a value. For GCSE you need four of them.

The four basic data types

Type	What it stores	Examples
String (`str`)	Text, written in quotes	`"hello"`, `"B"`, `"14"`
Integer (`int`)	A whole number	`14`, `-3`, `0`
Float (`float`)	A number with a decimal point	`1.62`, `3.0`, `-0.5`
Boolean (`bool`)	One of two values only	`True`, `False`

Checking a type with type()

types.py

print(type("hello"))
print(type(14))
print(type(1.62))
print(type(True))

Output

<class 'str'>
<class 'int'>
<class 'float'>
<class 'bool'>

How it works

type() tells you the data type of a value.
str is text, int is a whole number, float has a decimal point, bool is True or False.

Booleans: True and False

bool.py

is_logged_in = True
has_paid = False
print(is_logged_in)
print(type(has_paid))

Output

True
<class 'bool'>

How it works

A boolean stores one of just two values: True or False (note the capital letters).
Booleans are how a program records a yes/no fact.
They become very important for making decisions — the next topic.

Quotes change the type14 is an integer, but "14" is a string. They look the same on screen but behave differently: "14" + "14" gives '1414', while 14 + 14 gives 28.

Remember the fourstr, int, float, bool. Picking the right type prevents errors and surprises.

What you have learned

Every value has a type: str, int, float or bool.
Use type() to check a value's type.
A boolean is either True or False and records a yes/no fact.
Quotes make a value a string, even when it looks like a number.