Python not keyword is a logical operator which is usually used for figured out the negation or opposite boolean value of the operand. The Keyword ‘not’ is a unary type operator which means that it takes only one operand for the logical operation and returns the complementary of the boolean value of the operand. For example, if we will give false as an operand to the not keyword we get true as the value of returns.
Syntax: not var
Practical Application
The possible practical application of not keyword are:
- This keyword is mostly used for altering the boolean value.
- It is used with an if statement. In the if statement It is used for negating the condition
- ‘not’ keyword is also used with in keyword. It is used with in keyword when we are searching for the specific value in the collection of data.
Example 1: Basic example of not operator with true variable.
Python3
# variablea = Trueprint(not a) |
Output:
False
Example 2: Basic example of not operator with variable.
Python3
# variablea = Falseprint(not a) |
Output:
True
Example 3: Example with Specific condition.
As basic property of the ‘not’ keyword is that it is used to invert the truth value of the operand. So we can see here that the result of every value is inverted from their true value. At #5 we can see the compare operation result would be false, so negation of it we get True value. Similar, we can see all results are inverted.
Python3
# Python code to demonstrate# 'not' keyword# Function showing working of not keyworddef geek_Func(): # 1 Not with False boolean value geek_x = not False print('Negation of False : ', geek_x) # 2 Not with true boolean value geek_y = not True print('Negation of True : ', geek_y) # 3 Not with result of and operation geek_and = not(True and False) print('Negation of result of And operation : ', geek_and) # 4 Not with result of or operation geek_or = not(True or False) print('Negation of result of or operation : ', geek_or) # 5 Not with result of compare operation geek_Com = not (5 > 7) print('Negation of result of And operation : ', geek_Com)geek_Func() |
Output:
Negation of False : True Negation of True : False Negation of result of And operation : True Negation of result of or operation : False Negation of result of And operation : True
Example 4: In this Code, we show the working of ‘not’ operator with a different value other than boolean, and see how it works.
Python3
# Python code to demonstrate# 'not' keyword# Function showing working of not keyworddef geek_Func(): # Not with String boolean value geek_Str = "geek" print('Negation of String : ', not geek_Str) # Not with list boolean value geek_List = [1, 2, 3, 4] print('Negation of list : ', not geek_List) # Not with dictionary geek_Dict = {"geek": "sam", "collage": "Mit"} print('Negation of dictionary : ', not geek_Dict) # Not with Empty String geek_EDict = "" print('Negation of Empty String : ', not geek_EDict) # Not with Empty list geek_EList = [] print('Negation of Empty List : ', not geek_EList) # Not with Empty dictionary geek_EStr = {} print('Negation of Empty Dictionary : ', not geek_EStr)geek_Func() |
Output:
Negation of String : False Negation of list : False Negation of dictionary : False Negation of Empty String : True Negation of Empty List : True Negation of Empty Dictionary : True
In the above example we had seen that treating all the data types as operand with not keyword., ‘not’ treats true to all the data types who had value and false to those who were empty value.
Example 5: Example with the list
Python3
# Python code to demonstrate# 'not' keywordgeek_list = [5, 10, 20, 59, 134, 83, 95]# Function showing working of not keyworddef geek_Func(): # Using not with if statement if not geek_list: print("Inputted list is Empty") else: for i in geek_list: if not(i % 5): # Using not with in statement if i not in (0, 10): print("Multiple is not in range") else: print(i) else: print("The number is not multiple of 5")geek_Func() |
Output:
Multiple is not in range 10 MUltiple is not in range The number is not multiple of 5 The number is not multiple of 5 The number is not multiple of 5 Multiple is not in range
