Methods and Functions

Python Bool()

Python bool() is one of the Python programming language‘s data types. Booleans are derived from mathematics and arithmetic and are used to represent truth values. Booleans are, in reality, the fundamental building blocks of complicated algorithms. When programming, Booleans are used to evaluate expressions and produce either True or False results. Booleans enable the creation of logical conditions that define an application’s behaviour. To build more sophisticated logical conditions, Boolean Python operators are used. Knowing booleans aids in the creation of logical conditions in Python programs.

bool() Parameters

The bool() function converts a value into a boolean value (True or False). The bool function returns False if the provided value is False; else, it returns True. The syntax is as follows:

bool([value])

The bool() function can only take one parameter, as we can see from the syntax. It determines if a value is True or False. The bool() function returns False if no value is passed to it.

Source Code

Return Value from bool()

For all of the following values, the Boolean Python function returns False:

  • None
  • False
  • Zero number is passed in any numeric type, such as 0, 0.0, etc.
  • Empty list [], Empty tuple (), Empty String “”.
  • Empty dictionary {}.
  • Objects of Classes that implements __bool__() or __len()__ method, which returns False or 0

Except for the values stated above, this function returns True for all other values.

 Example: How bool() works?

We’ll check the output of the bool() function for the given values in the example below. We have a variety of data types with varied values, and we are printing the bool() function’s return value in the output.

                    

# empty list

lis = []

print(lis,’is’,bool(lis))

 

# empty tuple

t = ()

print(t,’is’,bool(t))

 

# zero complex number

c = 0 + 0j

print(c,’is’,bool(c))

 

num = 99

print(num, ‘is’, bool(num))

val = None

print(val,’is’,bool(val))

 

val = True

print(val,’is’,bool(val))

 

# empty string

str = ”

print(str,’is’,bool(str))

 

str = ‘Hello’

print(str,’is’,bool(str))

# empty list lis = [] print(lis,’is’,bool(lis))

# empty tuple t = () print(t,’is’,bool(t))

# zero complex number c = 0 + 0j print(c,’is’,bool(c))

num = 99 print(num, ‘is’, bool(num))

val = None print(val,’is’,bool(val))

val = True print(val,’is’,bool(val))

# empty string str = ” print(str,’is’,bool(str))

str = ‘Hello’ print(str,’is’,bool(str))

Output: 

                    

[] is False 

() is False 

0j is False 

99 is True 

None is False 

True is True

    is False 

Hello is True

Frequently Asked Questions

How do you write boolean in Python?

The True or False keywords define the Boolean Python type, which is one of the built-in data types given by Python. It’s most commonly used to indicate the truth values of expressions. The variable is a boolean data type, as indicated by the output <class ‘bool’>.

  • The SQL literals FALSE and TRUE are accepted as input for Boolean columns. The strings ‘FALSE’ and ‘TRUE,’ as well as the integers 0 and 1, are also accepted for use in a Boolean column or variable due to automatic coercion rules. The input is not case sensitive.
  • In expressions, the IS Boolean operator can be used. IS TRUE represents a BOOLEAN TRUE value, IS FALSE represents a BOOLEAN FALSE value, and IS UNKNOWN represents an Unknown (NULL) value. When working with Boolean values, IS UNKNOWN is a synonym for IS NULL.
  • ORDER BY BOOLEAN groups rows in the following order: FALSE, TRUE, NULL.
  • On BOOLEAN columns, the CREATE INDEX statement can be used to create an index.
  • The literals FALSE and TRUE are displayed as unquoted strings in Terminal Monitor output for a BOOLEAN column.
  • BOOLEAN columns or literals can be used with CASE expressions.

 How do you check boolean in Python?

True and truthy values exist in Python. If you run bool, values are evaluated as True. False and falsy values (values that return False from bool(variable)) exist in the same way. An empty list ([]), string (“”), dictionary ({}), None, and 0 are all false, but not strictly False.

You may need to differentiate between True/False and truthy/false values on occasion. If your code has to behave in one way when you pass an empty list, and in another, when you pass False, you can’t use if not value.

To check boolean:

  • Use the if variable or the if not variable to see if a variable is True/False (you don’t have to discriminate between True/False and truthy / falsy values). It’s the simplest and most efficient method.
  • Use is to verify whether a variable is explicitly True or False (rather than truthy/false).
  • Use if variable == 0 or if variable == [] to see if a variable is equal to 0 or if a list is empty.

 Can you use == for Boolean?

Yes, == can be used for Boolean. For example:

                    

print(pints_of_ice_cream_purchased == 8)

print(pints_of_ice_cream_purchased == 8)

How do you use Boolean in Python 3?

In Python 3, the keywords True and False can be used to specify a boolean value in your code. The following code generates two boolean values, which are then assigned to variables:

                    

mullet_looks_good = False

python_is_fun = True

mullet_looks_good = False python_is_fun = True

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