Data Types: int, float, str, bool

What You Will Learn

Every value in Python has a type. The type determines what you can do with the value. This lesson covers the four most important types.

int — Whole Numbers

int (integer) represents whole numbers — no decimal point:

age = 25
score = -10
year = 2026

print(type(age))

Expected output:

<class 'int'>

type() tells you what type a value is. You can do arithmetic with integers:

print(10 + 3)   # 13
print(10 - 3)   # 7
print(10 * 3)   # 30
print(10 // 3)  # 3  (integer division, rounds down)
print(10 % 3)   # 1  (remainder)

float — Decimal Numbers

float represents numbers with a decimal point:

height = 1.75
temperature = -3.5
pi = 3.14159

print(type(height))

Expected output:

<class 'float'>

Most arithmetic works the same as with integers:

print(10 / 3)    # 3.3333...  (regular division always returns float)
print(1.5 + 2.5) # 4.0
print(2.0 ** 3)  # 8.0  (exponentiation)

str — Text

str (string) represents text. Strings are always wrapped in quotes:

name = "Alice"
greeting = 'Hello, world!'
empty = ""

print(type(name))

Expected output:

<class 'str'>

You can join strings together with +:

first = "Hello"
second = "world"
print(first + ", " + second + "!")

Expected output:

Hello, world!

You cannot add a string and a number directly:

age = 25
print("I am " + age + " years old")  # TypeError!

Convert the number to a string first:

age = 25
print("I am " + str(age) + " years old")

Expected output:

I am 25 years old

bool — True or False

bool (boolean) has only two possible values: True and False:

is_raining = True
is_sunny = False

print(type(is_raining))

Expected output:

<class 'bool'>

Booleans come from comparisons:

print(10 > 5)    # True
print(10 < 5)    # False
print(10 == 10)  # True  (== checks equality)
print(10 != 5)   # True  (!= checks inequality)

You will use booleans constantly when making decisions in your programs (covered in a later lesson).

Converting Between Types

Python can convert between types:

# int to float
x = float(42)
print(x)        # 42.0

# float to int (truncates decimal)
y = int(3.9)
print(y)        # 3

# number to string
z = str(100)
print(z)        # "100"
print(type(z))  # <class 'str'>

# string to int (only works if the string looks like a number)
n = int("42")
print(n + 1)    # 43

What You Learned

In the next lesson, you will learn how to work with strings in more detail — slicing, searching, and formatting.