How to Check if a Variable Is or Is Not None in Python?

This article is the perfect choice for you if you are new to Python and need to learn the fundamentals of verifying None types in Python; in this post, we teach 6 methods to check if a variable has a “None” value. Read the rest. 🔚

No doubt, the idea of null is familiar to you if you’ve worked with other programming languages like C or Java. This is a common way to designate empty variables, pointers that don’t point anywhere, and default parameters that haven’t been explicitly specified. In such languages, null is frequently specified as 0, whereas null in Python has a distinct meaning.

In this post, we go into great detail about how Python handles null. What does the Python “None” keyword mean, and how do we check it? This article gives excellent examples to help you understand how Python handles null objects and variables. So without further ado, let’s get started with the topic.

What is “None” in Python?

The term  “None” is used to indicate a null value or precisely no value. None is distinct from 0 (zero), False, and an empty string. None is a distinct data type (NoneType).

Python defines null objects and variables with the term None. While None accomplishes certain things that null does in other languages. Suppose we assign None to more than one variable, all the variables with the None value point to the same object. 

Except for None itself, comparing None to anything always results in False. Let’s see a simple example to understand None in Python.

Code

# Example to understand None


myvar = None

print(myvar)



# A Function which returns nothing

def myfunction():

     pass
 

# Calling a function which returns nothing

myfunction()



# Print what our function will return

print("The Output of myfunction is:", myfunction())

Output

None

The output of myfunction is: None

Different Ways to Check for None in Python

Following are different ways to check whether a variable is None or the function returns None type:

1. Using comparing operator.
2. Using identity operator.
3. Using a dictionary data structure.
4. Using exception handling.
5. Using type function.
6. Using isinstance().

Method 1: Using Comparing Operator to Check for None

The Python equal == operator compares two objects’ values or determines their equivalence. Most of the time, we use the equal operator (==) to verify that two operands are equal and the not equal operator (!=) to verify that two operands are not equal. 

Now let’s see with the help of a simple example how we can check None in Python with the help of an equal operator:

Code

# Example of an equal operator to check None

# A Function which returns nothing

def myfunction():

     pass

 
# Calling a function which returns nothing

# Assign returned value to myvar

myvar=myfunction()



# Use if structure to check whether our myfunction returns None

if myvar == None:

    print ("myfunction is returning None")

else:

    print ("myfunction is not returning None")

Output

myfunction is returning None

Method 2: Using Identity Operator to Check None

We may compare objects using the identity operators (is, is not) in Python. If both variables on either side of the “is” operator refer to the same object, it evaluates to true. Otherwise, it would give us a false evaluation. 

Now let’s use a straightforward example to understand this method better:

Code

# Example of is Identity operator to check None

# A Function which returns nothing

def myfunction():

     pass
 

# Calling a function which returns nothing

# Assign returned value to myvar

myvar=myfunction()



# Use if structure to check whether our myfunction returns None

if myvar is None:

    print ("myfunction is returning None")

else:

    print ("myfunction is not returning None")

Output

myfunction is returning None

Method 3: Using Dictionary Data Structure to Check None

A dictionary is made up of a group of key-value pairs. Each key-value combination corresponds to a key and its corresponding value. Python’s dictionary is also known as an associative array. 

A list of key-value pairs can be defined as a dictionary by surrounding it in curly braces ({}). Each key is separated from its corresponding value by a colon (:). 

Now let’s see a simple example in which we see how we can use a dictionary to check None:

Code

# Example of a dictionary to check None

# Assign None to a variable

myvar = None



# Declare dictionary to check None

mydictionary = {None: 'None is stored in this variable'}

print(mydictionary[myvar])

Output

None is stored in this variable

Method 4: Using Exception Handling

Managing exceptions is crucial since they can cause a program’s execution to end unexpectedly. The try…exception block is used in Python to handle exceptions that result when doing any arithmetic operations on None type variables. 

For example.

Code

# Example of adding None with number

a = 10

b = None

print("Sum of a and b:", a+b)

Output

So the above code generates an error that we cannot add a None type variable to a number; that’s why we use try block here to handle this exception. Here is an illustration of how to use the try block to contain code that might cause an exception. 

An exception block comes after every try block. The exception block handles exceptions when they occur. Without the try block, the except block cannot be used. 

Let’s understand with a simple example how we can check None with the help of exception handling:

Code

# Example of adding None with number

a = 10

b = None

try:

    print("Sum of a and b:",a+b)

except:

    print("One of variables is of None type.")

Output

One of variables is of None type.

Method 5: Using the type function to check None

Python’s built-in function type() is used to determine the kind of data included in programme objects or variables. We can use the type function to check variable whether it is None. 

Let’s understand it with the help of a simple example:

Code

# Example of checking the type of variable

a = 10

b = None

print("Type of a is:",type(a))

print("Type of b is:",type(b))

Output

Type of a is: <class 'int'>

Type of b is: <class 'NoneType'>

Method 6: Using Isinstance Function to Check None

We can use the isinstance function to check whether the object is None type or not. If an object is an instance of the given type, the isinstance() function returns True; otherwise, it returns False. 

For example.

Code

# Example of checking None type variable with the help of isinstance()

b = None

if (isinstance(b, type(b))):

    print("The variable is of None type.")

Output

The variable is of None type.

Conclusion

To summarize the article on “how to check for None in Python”, we effectively demonstrate each and every method that can be used to determine whether a Python variable is None.

We covered six alternative approaches of checking None in Python, all of which are applicable in various circumstances. The most common and straightforward method for checking variables of the None type is the identity operator(is).

If you find this writing helpful, share it with your coding mates and let us know in the comment section below 🔽which method helps you most to solve your mystery of checking the None type.

Happy Coding!