Boolean Types in Python

What is a Boolean?

A Boolean is a data type that has only two possible values:

• True — represents truth
• False — represents falsehood

Booleans are commonly used in conditions, comparisons, and controlling the flow of a program.

Boolean Values

In Python, True and False are special constants (keywords) and must be capitalized exactly as shown.

Example:

is_sunny = True
is_raining = False

print(is_sunny)  # Output: True
print(is_raining) # Output: False

Boolean Expressions

Boolean values often result from expressions using comparison operators:

a = 10
b = 20

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

Using Boolean Values in Conditions

Booleans are used in control flow statements like if, while:

is_logged_in = True

if is_logged_in:
    print("Welcome back!")
else:
    print("Please log in.")

Output:

Welcome back!

Boolean Operators

Python has three logical operators to combine or invert boolean values:

Example:

a = True
b = False

print(a and b)  # False
print(a or b)   # True
print(not a)    # False

Truthy and Falsy Values

Besides True and False, other values are implicitly considered Boolean in conditions:

• Values considered False in Python include: False, None, 0, 0.0, "" (empty string), [] (empty list), {} (empty dict), set(), () (empty tuple)

• All other values are considered True

Example:

if 0:
    print("This won't print")
else:
    print("0 is considered False")

if "hello":
    print("Non-empty string is True")

Output:

0 is considered False
Non-empty string is True

Converting to Boolean with bool()

You can convert any value to a Boolean using the bool() function:

print(bool(0))       # False
print(bool(42))      # True
print(bool(""))      # False
print(bool("Python")) # True
print(bool([]))      # False
print(bool([1, 2]))  # True

Summary

• Boolean values in Python are True and False.
• Result from logical expressions or can be assigned directly.
• Used in conditions, loops, and logical operations.
• Logical operators: and, or, not.
• Many values have implicit Boolean context (truthy or falsy).
• Use bool() to convert values to Boolean explicitly.