Python Boolean

Boolean is a logical system in computer programming that returns the statement as true or false. The main intention is the representation of two truth values in the logic system of computer languages and Boolean. The expressions in the boolean method are OR, AND, XOR, NOT, etc. All these methods are used to compare the input values and return the result as true or false. For eg, there are comparisons such as 4 < 6, a < 6, a < b and Age < 18 are a few Boolean expressions. Therefore, the comparison 4 < 6 will predict the output as true always as 4 will always remain smaller than 6.

What is Python Boolean?

Like the boolean method, python boolean is a built-in data type that returns true or false in python programming. For instance, let us take the following expression that says: 7 <= 8 is True; however, 0 == 1 is False. Python Boolean operators will test for the identification of an object; let's say 'a is ‘b' is true if both an, as well as b, have the same id. This statement actually means that both a and b are the same object. So, whenever the user wants to compare the return values of similar data, he can make use of ==. Otherwise, if he is comparing two objects that are the same (be it boolean or anything else), you can make use of 'is'. 

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Let us see an example below to understand a basic example with python boolean:

x = 100

y = 50

if y > x:

  print("y is greater than x")

else:

  print("y is smaller than x")

Output:

y is smaller than x

Python Boolean Type

Let us see a few cases in python where the boolean method returns false. 

  • If a non-true value will be passed as input.
  • If the user passes “none”.
  • If the user passes an empty sequence like  (), [], etc
  • If the user passes Zero value in any num type, such as 0.0 etc
  • If the user inputs an empty mapping like {}.


Except for all these situations, the python bool() method will return true.

Python Booleans as Keywords:

 Let us see another example below to understand how bool() function works as a keyword in python: 

a = True
print(bool(a))

a = False
print(bool(a))

a = None
print(bool(a))

a = ()
print(bool(a))

a = 4
b = 8
print(bool(a == b))

a = {}
print(bool(a))

a = 0.0
print(bool(a))

a = 'Welcome to HKR Trainings'
print(bool(a))


Output:

True
False
False
False
False
False
False
True
>

Python Booleans as Numbers

Python’s built-in bool() method takes up numbers that can be further used as bool values. It can be any float number, an integer, or a complex number that has zero as a value that will be considered False, whereas if they have a positive or a negative value, it will be marked as True.


Let us see an example below to see how python boolean work as numbers:

variable1 = 0
print(bool(variable1))

variable2 = -6.2
print(bool(variable2))

variable3 = 1
print(bool(variable3))

Output:

False
True
True
>

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Comparison Operators

A comparison operator is used to compare the value of two inputs and it will either return True or False. This return type will be based on whether the argument's condition is fulfilled or not. A comparison operator is also called a relational operator in python. 

Python has six types of comparison operators which are less than (<), greater than(>), equal to(=), less than or equal to(<=), greater than or equal to(>=), and not equal to(!=).

  1. Python Less than operator: (<) This operator is used to check whether the input left value is less than that of the input value on the right or not.
  2. Python greater than operator: (>) This operator is used to check whether the input left value is greater than that of the input value on the right or not.
  3. Python equals operator: (=) This operator is used to check whether the input left value is equal to the input value on the right or not.
  4. Python Less than or equals operator: (<=) This operator is used to check whether the input left value is less than or even equals the input value on the right or not.
  5. Python greater than or equals operator: (<=) This operator is used to check whether the input right value is less than or even equals to the input value on the right or not.
  6. Python NOT operator: (!=) If the input values of two operands are not equal to each other, then this operator’s condition is true.

Let us see an example below to understand the python comparison operators:

x = 20
y = 10
z = 0


if ( x == y ):
   print("x is equal to y")
else:
   print("x is not equal to y")

if ( x != y ):
   print("x is not equal to y")
else:
   print("x is equal to y")

if ( x != y ):
   print("x is not equal to y")
else:
   print("x is equal to y")

if ( x < y ):
   print("x is less than y") 
else:
   print("x is not less than y")

if ( x > y ):
   print ("x is greater than y")
else:
   print ("x is not greater than y")

x = 5;
y = 10;
if ( x <= y ):
   print ("x is either less than or equal to y")
else:
   print ("x is neither less than nor equal to y")


if ( y >= x ):
   print ("y is either greater than  or equal to x")
else:
   print ("y is neither greater than  nor equal to x")

Output:

x is not equal to y
x is not equal to y
x is not equal to y
x is not less than y
x is greater than y
x is either less than or equal to y
y is either greater than  or equal to x
>

Chaining Comparison Operators

Chaining is a process done with the comparison operators in python which returns ‘True’ if all values of operands are equal to each other. In case there is a single value that is not equal, then the output will be ‘False’. 

Comparisons within boolean values: Either True or False.
Comparisons can be randomly chained in python.

x < y <= z is equivalent to x < y and y <= z

If b is calculated only once, c will not be evaluated when a < b is false. Let us see an example below to see how python chaining comparison operators work:

a = 10

print(10 < a < 20)

print(20 < a < 30 )

print(a < 10 < a*10 < 100)

print(20 > a <= 6)

print(10 == a > 7)

Output:

False

False

False

False

True

>

The IS operator

Boolean operators in python are the ones that take different inputs as operands and further return Boolean values as the output. This is a type of identity operator which returns ‘True’ in case the operands values of the same object are exactly the same. Let us understand this with an example below:

a = 4

b = 4

c = 'Welcome'

d = 'Welcome'

e = [10,20,30]

f = [10,20,30]

print(a is not b)


Output:

False

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The IN operator

This is a type of membership operator which returns ‘True’ in case the input value is present in the given sequence. Let us understand this with an example below:

o = 'Welcome to HRK Training'

p = {1:'x',2:'y'}

print('R' in o)


Output:

True

>

Equality and Inequality

Two operands are said to fall inequality if both of them have the same value. The user can check it for any numerical, strings, etc.

Two operands are said to be unequal in case both of them do not match the same value. The user can check if two operands are unequal by making use of the exclamation point along with an equals sign in python.

Boolean Operators:

The operators in python are termed as the symbols which are used to perform some kind of arithmetic as well as logical calculations. There are input values on which computations are performed which are also called operands and they have operators which are denoted by +, -, /, *, etc.

The OR Operator

It is a type of logical operator which returns true when one of the input values is true. We can write it as x OR y. Let us see an example to understand the OR operator in python: 

x = 10
y = 10
z = -10

if x > 0 and y > 0 and z > 0:
print("The nos are greater than 0")
 
if x > 0 and y > 0:
print("The nos are greater than 0")
else:
print("Only 1 no is not greater than 0")

Output:

The nos are greater than 0
>

Other Boolean Operators

It is written in a mathematical theory of logic that, except OR, AND, and NOT, no other operators are required to perform computations. All the functions that will be performed by any other operator can already be performed with these three defined operators. Even the operators which take in three input values can also work in terms of operators with just two inputs. AND and OR operators both make a pair of very useful operators in computer languages.

Except for these, we have a total of sixteen possible 2-input Boolean operators. However, they are not needed while coding much. Hence, the only built-in operators used in python are True, False, OR, NOT, AND. 

Python Boolean Testing

As we have understood from our discussion about boolean in python, we have known that the major use of it is done in an ‘if’ statement. It finds out if the input argument is true or false. Check out the python code below:

if(1 == 2):
    print("False")

if (1 == 1):
    print("yes")


Output:

yes

While testing the boolean in python, print() is that one expression that will evaluate to ‘True’. However, the user can give any value to it in python. The values which are returned as True are called truthy, whereas the values which are returned as false are termed to be falsy.

None as Boolean Value

The none statement is always termed as falsy. You must have seen it in ‘if’ statements to find the sentinel value. Whereas, the better way of checking is by ‘None’. None as a boolean value can be important in combining it with a short evaluation to have a default value. 

bool(None)

False

Number as Boolean Value
  • bool(z) is equal to z != 0. The statement means that the only falsy integer will be 0.
  • All the integers which are not zero are truthy. This is correct for float numbers, including special numbers such as infinity or (NAN) Not a Number. 
  • Infinity and NAN are never equal to 0, which means they belong to the truthy category.
  • Fractions can also be falsy only when they tend to be equal to zero. 
  • Similarly, decimals can also be falsy only when they tend to be equal to zero.
Sequence as Boolean Value

In python, objects have a function called len(). It will be falsy only when the output of len() is equal to 0. It won’t matter if it is a list, tuple, dictionary, or a set, if the len() is 0, it will be falsy.

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Conclusion

We have understood from this article that python boolean is a built-in data type that has a lot of useful applications in python. The user can make use of booleans with operators such as OR, AND, NOT, IN, IS, Equals to, etc., and we have covered all these operators in this article. These operators actually compare the input values and check for the relation between them as the user wants, such as equality or identity. We have also seen how python booleans can be manipulated as boolean operators and described boolean testing, which works with python if and controls the flow of user's python codes, which can either be based on truthy or falsy criteria of the statement.

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Amani
Amani
Research Analyst
As a content writer at HKR trainings, I deliver content on various technologies. I hold my graduation degree in Information technology. I am passionate about helping people understand technology-related content through my easily digestible content. My writings include Data Science, Machine Learning, Artificial Intelligence, Python, Salesforce, Servicenow and etc.