In this tutorial, you'll learn about the Python Boolean data type, how to use it, and how Python evaluates truthy and falsy values.

Introduction to Boolean Data Type

In programming, we often need to check conditions—whether something is true or false—to control the flow of the program.

Python provides a special data type called bool that has only two values:

True
False

Note: These must start with capital T and F respectively.

Example:

is_active = True
is_admin = False

These are boolean variables that hold either True or False.

Booleans in Comparisons

When you compare two values, the result is a boolean:

x = 20
y = 10

print(x > y)  # True
print(x < y)  # False

Comparison also works with strings:

x = 'a'
y = 'b'

print(x > y)  # False
print(x < y)  # True

The bool() Function

You can check the truthiness of a value using the bool() function:

print(bool('Hi'))   # True
print(bool(100))    # True
print(bool(0))      # False

Truthy and Falsy Values

  • Truthy values are those that evaluate to True when passed to bool()

  • Falsy values evaluate to False

Falsy values in Python include:

  • The number 0

  • An empty string ''

  • The value False

  • The special value None

  • An empty list []

  • An empty tuple ()

  • An empty dictionary {}

Any other value is considered truthy.

Exercises

Exercise 1

Declare a variable is_student and assign True to it. Then print its value:

is_student = True
print(is_student)

Exercise 2

Compare two numbers using > and < and print the results:

a = 5
b = 10
print(a > b)  # False
print(a < b)  # True

Exercise 3

Use the bool() function with different types of values:

print(bool(0))        # False
print(bool(42))       # True
print(bool(''))       # False
print(bool('Python')) # True

Exercise 4

Write a small program that checks if a string is empty or not:

user_input = ''
if bool(user_input):
    print("Input is not empty")
else:
    print("Input is empty")

Summary

  • The Boolean data type in Python includes only True and False

  • You can use comparison operators and the bool() function to evaluate expressions

  • Falsy values include 0, '', False, None, [], (), {}

  • Any value not falsy is considered truthy

  • Booleans are fundamental for control flow and decision-making in Python

Practice comparing values and testing expressions with bool() to master how Python evaluates truth and falsehood.

 

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