Python NULL – How to Identify Null values in Python?

Python null value: Here we see, what Python null means and what the NONE type is. In various computer languages, the term ‘null‘ refers to an empty variable or a reference that points to nothing. ‘null’ is the same as ‘zero.’ In Python, however, there is no ‘null’ keyword. Instead, the object ‘None‘ is utilized for this purpose.

NULL in Python:

What is null in python: When a function does not have anything to return, i.e. does not have a return statement, the output is None.

In other words, the None keyword is used here to define a null variable or object. None is an object and a data type of the NoneType class.

Example

Approach:

Create a function say null_fun().
Inside the function, take a variable and initialize it with some random number.
Take another variable and initialize it with some random number.
In the main function, call the above-declared function null_fun() and print it.
The Exit of the Program.

Below is the implementation:

# Create a function say null_fun()
def null_fun():
    # Inside the function, take a variable and initialize it with some random number
    num1 = 5
    # Take another variable and initialize it with some random number
    num2 = 7
# In the main function, call the above declared function null_fun() and print it
print(null_fun())

Output:

None

Explanation:

Here the function doesn't return anything hence it prints 'None' as output

Example

Null value in python: When we assign None to a variable, it points to the same object as all the variables that are assigned to it. There are no new instances created.

In Python, unlike in other languages, null is an object in itself, not just a synonym for 0.

type(None)

Output:

NoneType

Python Declaration of Null Variables

Null value python: Python does not declare null variables by default. In other words, an undefined variable is not the same as a null variable.

Example

print(x)

Output:

Output showing an Error due to Undeclaration of Variable

Explanation:

Here the variable x is undefined, hence it raises an error

Python Code to Check whether the variable is none

Null check in python: We use the ‘is’ operator or the ‘==’ operator to determine whether a variable is None or not

1)Check Using ‘is’ operator:

Example

Approach:

Take a variable and initialize its value with None.
Check if the above variable value is None using the ‘is’ operator and if conditional statement.
If it is true, then print ‘The Output is None’.
Else print “The Output is not None’.
The Exit of the Program.

Below is the implementation:

# Take a variable and initialize its value with None
x = None
# Check if the above variable value is None using the 
# 'is' operator and if conditional statement
if x is None :
    # If it is true, then print 'The Output is None'                 
    print("The Output is None")
else :
    # Else print "The Output is not None'
    print("The Output is not None")

Output:

The Output is None

2)Check Using ‘==’ operator:

Approach:

Take a variable and initialize its value with None.
Check if the above variable value is None using the ‘==’ operator and if conditional statement.
If it is true, then print ‘The Output is None’.
Else print “The Output is not None’.
The Exit of the Program.

Below is the implementation:

# Take a variable and initialize its value with None
x = None
# Check if the above variable value is None using the 
# '==' operator and if conditional statement
if (x == None):
    # If it is true, then print 'The Output is None'                 
    print("The Output is None")
else :
    # Else print "The Output is not None'
    print("The Output is not None")

Output:

The Output is None

A Brief Recall

A null variable is defined with the None keyword.
None is not same as zero.
None as an immutable type.
None can be used to indicate missing values as well as default parameters.

NULL in Python:

Python Declaration of Null Variables

Python Code to Check whether the variable is none

A Brief Recall

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