Data Types

Learn how Python stores different kinds of information so you can write clearer programs and begin working with real data.

Skill Level: Beginner
Prerequisites: Variables
Estimated Time: 20 minutes

Story Time

In the previous lesson, you learned that a variable can store information. Now the next question is: what kind of information is being stored?

Not all values are the same. A student's name is text, an exam score might be a whole number, an average could include decimals, and whether a student submitted work on time may be either true or false.

Python needs to recognize these differences so it can work with data correctly. Understanding data types is one of the first steps toward writing useful programs and analyzing real datasets.

What You’ll Learn

By the end of this lesson, you will be able to:

• Explain what a data type is.
• Identify four common Python data types.
• Create variables using different data types.
• Use the type() function to inspect a value.
• Recognize common beginner mistakes when working with data types.

What Is a Data Type?

A data type tells Python what kind of value is stored in a variable.

Look at this example:

name = "Emma"
age = 22
height = 165.5
is_student = True

These are all variables, but they do not store the same kind of information. One stores text, one stores a whole number, one stores a decimal number, and one stores a true-or-false value.

Four Common Data Types

In this course, you will frequently use these four Python data types:

Data Type	Meaning	Example
str	Text	"Emma"
int	Whole number	22
float	Decimal number	165.5
bool	True or False	True

These are enough to begin writing meaningful beginner programs and understanding how values behave in Python.

Strings

A string, written as str, stores text.

course = "Data Visualization"
print(course)

Output:

Data Visualization

Strings must be written inside quotation marks. Without quotation marks, Python will not treat the value as text.

Integers

An integer, written as int, stores a whole number.

students = 45
print(students)

Output:

45

Integers do not include decimal points. They are often used for counts, ages, and quantities.

Floating-Point Numbers

A floating-point number, written as float, stores a number with a decimal point.

temperature = 98.6
print(temperature)

Output:

98.6

Floats are useful for measurements, averages, percentages, and calculations where decimal values matter.

Boolean Values

A Boolean, written as bool, stores one of only two values:

• True
• False

Example:

is_registered = True
print(is_registered)

Output:

True

Booleans are useful when a program needs to make decisions, check conditions, or track whether something is true or false.

Using type()

Python provides the type() function to show the data type of a value or variable.

name = "Emma"
print(type(name))

Output:

<class 'str'>

Another example:

score = 95
print(type(score))

Output:

<class 'int'>

This is a helpful tool when you are unsure how Python is interpreting a value.

Worked Example

The following example checks the type of several variables at once:

name = "Emma"
age = 22
height = 165.5
is_student = True

print(type(name))
print(type(age))
print(type(height))
print(type(is_student))

Output:

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

This example shows that different kinds of values can be stored in different variables, and Python keeps track of each type automatically.

Quick Check

Before moving on, try identifying the data type of each value on your own.

Value	Data Type
"Python"	?
100	?
3.14	?
False	?

You can test your answers in Google Colab using type().

Practice in the Notebook

Notebook

Open in Google Colab

Practice this lesson in a live notebook.

After completing the activity in Google Colab, mark it as complete below.

Create the following variables in Google Colab:

• Your name
• Your age
• Your GPA, or any decimal value
• Whether you enjoy programming

Then use type() to display the data type of each variable.

Here is a model to get started:

name = "Ava"
age = 20
gpa = 3.8
enjoys_programming = True

print(type(name))
print(type(age))
print(type(gpa))
print(type(enjoys_programming))

Challenge

A library stores information about books. Create variables for:

• Book title
• Number of pages
• Price
• Whether the book is available

Then display both the values and their data types.

This is good practice because it helps you think about how real information is represented in a program.

Common Mistakes

Forgetting quotation marks

Incorrect:

city = Gainesville

Correct:

city = "Gainesville"

Without quotation marks, Python does not recognize Gainesville as a text value.

Writing numbers as text

age = "21"

This looks like a number, but Python treats it as text because it is inside quotation marks.

Correct:

age = 21

Incorrect Boolean capitalization

Incorrect:

registered = true

Correct:

registered = True

Python is case-sensitive, so Boolean values must begin with a capital letter.

Key Takeaways

• A data type tells Python what kind of value is stored in a variable.
• Four common beginner data types are str, int, float, and bool.
• Strings store text, integers store whole numbers, floats store decimals, and Booleans store True or False.
• The type() function helps you check how Python is interpreting a value.
• Understanding data types will help you write more accurate programs and prepare you for working with real datasets.

Self Evaluation

Check Your Understanding

1. What does a data type describe?

The color of a variableThe kind of value stored in a variableThe location of a fileThe name of a function

2. Which data type is used to store text in Python?

`int``float``str``bool`

3. Which of the following is a floating-point number?

`42``"42"``True``42.5`

4. What does the `type()` function do?

It changes text into numbersIt tells you the data type of a valueIt prints a chartIt saves a notebook

5. Which Boolean value is written correctly in Python?

`true``false``TRUE``True`

Continue Your Journey

In the next lesson, you will learn about type conversion, which allows you to change one data type into another when needed.