Boolean in Python: Simplified Examples (2023)

Boolean data type in Python is a data type that represents one of two possible values, either True or False. We use Python Boolean data types to perform logical operations in order to make certain decisions when the program is running.

The True value refers to when the condition(s) specified is considered to be true or valid, while the False value refers to when the condition(s) specified is false or not valid.

The importance of these boolean output values (true or false) is to control the flow of a program especially when certain decisions are to be made. The most common use cases in boolean data types are when we want to use conditional statements, such as if statements. The purpose of this is to execute or not to execute certain code blocks based on the boolean output (True or False).

How to compare two values and return Boolean output in Python

In Python, we can perform comparisons between two values and it returns a boolean value as a result. During the comparison we can use different comparison operators such as greater than, less than or equal.

In this section, we provided an example that demonstrates how to compare two values using various comparison operators and obtain Boolean results

Example: How to compare two values and return Boolean output in Python while using different comparison operators:

# How to compare two values and return Boolean ouput in Python

a = 20
b = 30

print(a == b)
print(100 < b)
print(b > a)
print(20 >= a)
print(90 >= a)
print(b != a)

Output:

False
False
True
True
True
True

Boolean in Control Flow: How to Use ‘if’ Statements to Conditionally Execute Code Blocks in Python

We can use a if statement to conditionally execute a block of code after specified conditions become true. In the following example, we show how to use the ‘if’ statement and conditionally execute a block of code in Python.

Example: How to use if statements to conditionally execute Code Blocks in Python while using different comparison operators:

# How to Use 'if' Statements to Conditionally Execute Code Blocks in Python

a = 20
b = 30

if a > b:
    print(a > b, ": a is greater than b")

if a < b:
    print(a < b, ": a is less than b")

if a == b:
    print(a == b, ": a and b are equal")

if a != b:
    print(a != b, ": a and b are not equal")

if a > b:
    print(a > b, ": a is greater than b")
else:
    print(a < b, ": a is not greater than b")

Output:

True : a is less than b
True : a and b are not equal
True : a is not greater than b

Boolean in Control Flow: How to Conditionally Execute Code Blocks Using the bool() Function and ‘if’ Statements in Python

In this section, we also show you how to use the bool() function within if statements to determine the Boolean value of different expressions.

• If the bool() function contains a non-empty string, a non-zero number, or a non-empty container (such as lists, tuples, sets, and dictionaries), the condition will be evaluated to True. Therefore, the corresponding block of code within the if statement is executed.

• On the other hand, if the bool() function contains empty strings, the number 0, and empty containers are considered False. Therefore, the corresponding block of code within the if statement will not be executed, and if there is an alternative else statement is provided, the code block within the else statement will be executed instead.

Example: How to conditionally execute code blocks using the bool() function and ‘if’ statements in Python:

# How to Conditionally Execute Code Blocks Using the bool() Function and 'if' Statements in Python
a = 20
b = 30

if bool("Python"):
    print(bool("Python"), "Yes there is value with a ", type("Python"), "type")

if bool(a):
    print(bool(a), "Yes there is value with a ", type(a), "type")

if bool(a > b):
    print(bool(a > b), "Yes a is less than b ")

if bool(""):
    print(bool(""), "Yes is not empty")
else:
    print(bool(""), "Becouse is empty")

Output:

True Yes there is value with a  <class 'str'> type
True Yes there is value with a  <class 'int'> type
True Yes a is less than b
False Becouse is empty

Boolean in Control Flow: How to Use ‘for’ loop to Conditionally Execute Code Blocks in Python

Similar to the if statement, in Python, we can also use a for loop to conditionally execute code blocks based on specific conditions. The Python loop iterates over a sequence of elements and executes the block of code as long as the specified condition is True.

Example: How to use the ‘for’ loop to conditionally execute code blocks in Python:

# How to use 'for' loop to conditionally execute code blocks in Python
a = 10
b = 20
var_str = "Python"

for i in var_str:
    if a < b:
        print(a < b, ": a is less than b")
    else:
        print(a < b, ": a is not less than b")

for i in "Loop":
    if a > b:
        print(a > b, ": a is greater than b")
    else:
        print(a > b, ": a is not greater than b")

Output:

True : a is less than b
True : a is less than b
True : a is less than b
True : a is less than b
True : a is less than b
True : a is less than b


True : a is not greater than b
True : a is not greater than b
True : a is not greater than b
True : a is not greater than b

Boolean in Control Flow: How to Use ‘while’ loop to Conditionally Execute Code Blocks in Python

Similar to the for loop, Python enables us also to use a while loop to conditionally execute code blocks based on a specific condition. As mentioned earlier, the loop continues to execute the block of code as long as the condition is true. The only time the loop stops is when the specified condition becomes false, when this happen, the loop will be terminated and the program continues with the next line of code.

Example: How to use ‘while’ loop to conditionally execute code blocks in Python:

# How to use 'while' loop to conditionally execute code blocks in Python
a = 10
b = 20
c = 12

while a < b:
    print(a < b, ": a is less than b")
    a = a + 1

while b > c:
    if a > b:
        print(a > b, ": a is greater than b")
    else:
        print(a < b, ": a is not greater than b")
    b = b - 1

Output:

True : a is less than b
True : a is less than b
True : a is less than b
True : a is less than b
True : a is less than b
True : a is less than b
True : a is less than b
True : a is less than b
True : a is less than b
True : a is less than b


False : a is not greater than b
True : a is greater than b
True : a is greater than b
True : a is greater than b
True : a is greater than b
True : a is greater than b
True : a is greater than b
True : a is greater than b

How to Evaluate Variables and Check for Empty Values Using the bool() Function in Python

In this section, we check if a variable with a certain value passed in the bool() function is True or False. Note: the bool() function is used to evaluate various variables and check if they are empty or not. Therefore, the bool() function in Python evaluates each value based on its truthiness and considers the following conditions.

• bool()function: returns True unless the argument passed is a non-empty string, non-zero numbers, and non-empty containers (such as lists, tuples, sets, and dictionaries).
• While the empty strings, the number 0, and empty containers are considered False.

Example: How to evaluate variables and check for empty values using the bool() function in Python:

# How to Evaluate Variables and Check for Empty Values Using the bool() Function in Python
a = 20
b = 30
c = None
d = []

print(bool(a))
print(bool(b))
print(bool(c))
print(bool(d))
print(bool(""))
print(bool(0))

Output:

True
True
False
False
False
False

How to Create a Function that Returns a Boolean Value in Python

It is important to create a function in a programming language, therefore, for some functions we expect them to return a Boolean value, especially in Python.

First, we need to create or define a function that includes a Boolean expression and uses the return statement to return the result of that expression. See the following example of how to do that.

Example: How to create a function that returns a Boolean value in Python:

# How to Create a Function that Returns a Boolean Value in Python

def fun_name(var_name):
    if bool(var_name):
        return True
    else:
        return False

# Call the function
print(fun_name("Mike"))
print(fun_name(""))

def fun_even_number(var_num):
    if var_num % 2 == 0:
        return True
    else:
        return False

# Call the function
print(fun_even_number(6))
print(fun_even_number(5))

Output:

True
False
True
False

Boolean Operators: Exploring the Logical Operators (and, or, not) in Python

In Python, we can use the logical operators such as and, or, and not to combine and manipulate Boolean values. These operators will allow you to perform logical operations on Boolean expressions, resulting in a Boolean output.

Benefits of Boolean Logical Operators (and, or, not)

Using logical Boolean operators is useful especially:

• When combining and manipulating Boolean values in conditional statements, loops, and other control flow structures.
• They allow you to create more complex Boolean expressions by combining simpler conditions.

• It is also beneficial to use as short-circuit evaluation for optimizing code and avoiding unnecessary computations when the result is already determined by the first operand.

• There is also a benefit when you master the usage of logical operators, you can effectively combine and manipulate Boolean values to control the flow of your program and make decisions based on conditions in Python.

How to use and Operator to Perform Logical Operations in Python

Using the and operator in Python returns True value if both operands evaluate to True. Otherwise, it returns False value.

This is used to perform short-circuit evaluation, which means that if the first operand is False, the second operand is not evaluated.

Example: How to use Python’s andLogical Operator to perform logical operations in Python:

# Example 1
a = True
b = False

result = a and b
print(result)  # Output: False

# Example 2
a = True
b = True

result = a and b
print(result)  # Output: True

Output:

False
True

How to use or Operator to Perform Logical Operations in Python

Using the or operator in Python returns True value if at least one of the operands evaluates to True. If both operands are False, it returns False value as boolean.

This is also used to perform short-circuit evaluation, so if the first operand is True, the second operand is not evaluated.

Example: How to use Python’s orLogical Operator to perform logical operations in Python:

# Example 1
a = True
b = False

result = a or b
print(result)  # Output: True

# Example 2
a = False
b = False

result = a or b
print(result)  # Output: False

Output:

True
False

How to use not Operator to Perform Logical Operations in Python

The not operator in Python negates the Boolean value of its operand. If the operand is True, it returns False, and if the operand is False, it returns True.

It is a unary operator, which means it operates on a single operand.

Example: How to use Python’s notLogical Operator to perform logical operations in Python:

# Example 1
a = True

result = not a
print(result)  # Output: False

# Example 2
a = False

result = not a
print(result)  # Output: True

Output:

False
True

Boolean Expressions: how to construct complex Boolean expressions using comparison operators and logical operators.

Boolean expressions can be constructed using comparison operators and logical operators In Python. These expressions evaluate to either True or False based on the conditions specified.

By combining comparison and logical operators, you can create complex Boolean expressions to make decisions and control the flow of your program.

Complex Boolean Expressions can be built using the following procedures:

• Complex Boolean expressions are created by combining multiple comparisons and logical operators to form more intricate conditions.
• Parentheses can be used to control the order of evaluation and ensure desired precedence.

Example: How to create complex boolean expressions using comparison operators and logical operators In Python:

a = 5
b = 10
c = 7
result = (a < b) and (c != 8) or (a > 0)
print(result)  # Output: True

Output:

True

This means knowing how to construct complex Boolean expressions, you can create sophisticated conditions to control the flow of your program. As you saw above, these expressions are also used in if statements, loops (for loop, while loop), and other control flow structures to make decisions based on multiple conditions.

As a programmer, it is good for you to understand how to use comparison and logical operators and how they can be combined to empower you to create expressive and dynamic logic within your Python programs.

Conclusion

In this tutorial, we discussed the Python boolean data type, as we know the boolean values are very important and fundamental in programming as they allow us to control the flow of our code based on conditions we specified and make decisions accordingly. The examples provided in the above sections clearly indicate how to perform various logical operations and make decisions during our program executions.

We have seen how to compare two values and return Boolean output, we also show you how to use if and else Statements to conditionally execute code blocks or repeatedly execute a block of code using for and while loops. The examples also include how to use the bool() function in Python, this facilitates us to understand how to evaluate variables and check for empty values. Additionally, we demonstrated how to create functions that Return a Boolean value in Python.

We also discussed the Logical Operators (and, or, not) in Python and how to create complex Boolean Expressions while combining multiple comparisons and logical operators. If you need more examples and Python code practices you can refer to these cheat sheets.