Python not Keyword

---

---

In Python, not keyword is one of the logical operator. If the given condition is True it will result in False. If the given condition is False it will result in True. It is a case-sensitive keyword.

The not keyword operation is performed only with one operand. It can be used in conditional statements, loops, functions to check the given condition.

Syntax

Here, is the basic syntax of Python not keyword −

not condition

Let us consider A be the condition. If the A is True then it will return False. When A is False it will return True. Here, is the Python not keyword truth table −

A	not A
True	False
False	True

Example

Following is an basic example of Python not keyword −

var1=1
result_1=not var1
print("The Result of not operation on",var1,":",result_1)
var2=0
result_2=not var2
print("The Result of not operation on",var2,":",result_2)

Output

Following is the output of the above code −

The Result of not operation on 1 : False
The Result of not operation on 0 : True

Using 'not' in if statement

We can use not keyword along with if-statement. When the condition is False the if block of code is not executed, To make the code executable we need to make the False condition to True we use not operator before the condition.

Example

Here, we have assigned the value to the variable it is considered as a True value so when we placed a not before the condition it resulted as False so else block is executed −

var1=45
if not var1:
    print("Hello")
else:
    print("Welcome to TutorialsPoint")

Output

Following is the output of the above code −

Welcome to TutorialsPoint

Using 'not' in while loop

The not can be used with while loop. We can iterate while a specified condition is not fulfilled by using the not operator in a while loop.

Example

In the following example we have used not in while loop −

def prime_num(n):  
  i = 2  
    
  while not i > n:  
    for j in range(2, i//2):  
      if i%j == 0:  
        break  
    else: print(i,end=' ')  
    i += 1  
  
# Calling the function  
prime_num(10)  

Output

Following is the output of the above code −

2 3 4 5 7