Nonetype object is not callable ошибка

You will encounter the TypeError: ‘NoneType’ object is not callable if you try to call an object with a None value like a function. Only functions respond to function calls.

In this tutorial, we will look at examples of code that raise the TypeError and how to solve it.

TypeError: ‘nonetype’ object is not callable

Calling a function means the Python interpreter executes the code inside the function. In Python, we can only call functions. We can call functions by specifying the name of the function we want to use followed by a set of parentheses, for example, function_name(). Let’s look at an example of a working function that returns a string.

# Declare function

def simple_function():

    print("Hello World!")

# Call function

simple_function()

Hello World!

We declare a function called simple_function in the code, which prints a string. We can then call the function, and the Python interpreter executes the code inside simple_function().

None, string, tuple, or dictionary types do not respond to a function call because they are not functions. If you try to call a None value, the Python interpreter will raise the TypeError: ‘nonetype’ object is not callable.

Let’s look at examples of raising the error and how to solve them.

Example #1: Printing Contents From a File

Let’s look at an example of a program that reads a text file containing the names of famous people and prints the names out line by line.

The text file is called celeb_names.txt and contains the following names:

Leonardo DiCaprio

Michael Jordan

Franz Kafka

Mahatma Gandhi

Albert Einstein

The program declares a function that reads the file with the celebrity names.

# Declare function

def names():
    
    with open("celeb_names.txt", "r") as f:
        
        celebs = f.readlines()
        
        return celebs

The function opens the celeb_names.txt file in read-mode and reads the file’s contents into the celebs variable. We will initialize a variable to assign the celebrity names.

# Initialize variable 

names = None

We can then call our get_names() function to get the celebrity names then use a for loop to print each name to the console.

# Call function

names = names()

# For loop to print out names

for name in names:

    print(name)

Let’s see what happens when we try to run the code:

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
1 names = names()

TypeError: 'NoneType' object is not callable

Unfortunately, we raise the NoneType object is not callable. This error occurs because we declared both a function and a variable with the same name. We declared the function first then the variable declaration overrides the function declaration. Any successive lines of code referring to names will refer to the variable, not the function.

Solution

We can either rename the function or the variable to solve this error. Adding a descriptive verb to a function name is a good way to differentiate from a variable name. Let’s change the function name from names() to get_names().

# Declare function with updated name

def get_names():

    with open("celeb_names.txt", "r") as f:

        celebs = f.readlines()

        return celebs

# Initialize variable with None

names = None

# Call function and store values in names variable

names = get_names()

# Loop over all names and print out

for name in names:

    print(name)

Renaming the function name means we will not override it when declaring the names variable. We can now run the code and see what happens.

Leonardo DiCaprio

Michael Jordan

Franz Kafka

Mahatma Gandhi

Albert Einstein

The code successfully works and prints out all of the celebrity names.

Alternatively, we could remove the initialization, as it is not required in Python. Let’s look at the revised code:

# Declare function with updated name

def get_names():

    with open("celeb_names.txt", "r") as f:

        celebs = f.readlines()

        return celebs

# Call function and store values in names variable without initializing

names = get_names()

# Loop over all names and print out

for name in names:

    print(name)

Leonardo DiCaprio

Michael Jordan

Franz Kafka

Mahatma Gandhi

Albert Einstein

Example #2: Calling a Function Within a Function

Let’s look at an example of two functions; one function executes a print statement, and the second function repeats the call to the first function n times.

def hello_world():

    print("Hello World!")

def recursive(func, n): # Repeat func n times

    if n == 0:

        return
    
    else:
        
        func()
        
        recursive(func, n-1)

Let’s see what happens when we try to pass the call to the function hello_world() to the recursive() function.

recursive(hello_world(), 5)

TypeError                                 Traceback (most recent call last)
      1 recursive(hello_world(), 5)

      3         return
      4     else:
      5         func()
      6         recursive(func, n-1)
      7 

TypeError: 'NoneType' object is not callable

Solution

To solve this error, we need to pass the function object to the recursive() function, not the result of a call to hello_world(), which is None since hello_world() does not return anything. Let’s look at the corrected example:

recursive(hello_world, 5)

Let’s run the code to see the result:

Hello World!

Hello World!

Hello World!

Hello World!

Hello World!

Summary

Congratulations on reading to the end of this tutorial. To summarize, TypeError’ nonetype’ object is not callable occurs when you try to call a None type value as if it were a function. TypeErrors happen when you attempt to perform an illegal operation for a specific data type. To solve this error, keep variable and function names distinct. If you are calling a function within a function, make sure you pass the function object and not the result of the function if it returns None.

For further reading on not callable TypeErrors, go to the articles:

• How to Solve Python TypeError: ‘tuple’ object is not callable.
• How to Solve Python TypeError: ‘bool’ object is not callable.
• How to Solve Python TypeError: ‘_io.TextIOWrapper’ object is not callable.

To learn more about Python, specifically for data science and machine learning, go to the online courses page on Python.

Have fun and happy researching!

“TypeError: ‘NoneType’ object is not callable” is a common python error that shows up in many ways. What is the cause of it and how to solve it? Let’s follow our article, and we will help you.

What is the cause of this error?

When you attempt to call an object with a None value, such as a function, you will get the TypeError: “NoneType” object is not callable error message. Function calls only have responses from functions.

Example code 1: Attribute and Method have the same name

class Student:
    def __init__(obj):
        obj.fullname = None

    def fullname(obj):
        return obj.fullname # Same name with the method
		
def printMsg():
    print('Welcome to LearnShareIT')
    
def msgStudent(name, function):
    print("Hi", name)
    function() 
	
exStudent = Student()
exStudent.fullname() # TypeError: 'NoneType' object is not callable

Error Message

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-4-65eab4cbbd19> in <module>
     14 
     15 exStudent = Student()
---> 16 exStudent.fullname()

TypeError: 'NoneType' object is not callable

Example code 2: Misunderstand when calling a function

class Student:
    def __init__(obj):
        obj.fullname = None

    def getFullName(obj):
        return obj.fullname
		
def printMsg():
    print('Welcome to LearnShareIT')
    
def msgStudent(name, function):
    print("Hi", name)
    function() # Calling None object as a function 
	
exStudent = Student()
exStudent.fullname = "Robert Collier"

msgStudent(exStudent.getFullName(), printMsg()) # TypeError: 'NoneType' object is not callable

Error Message

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-16-618076368e04> in <module>
     16 exStudent.fullname = "Robert Collier"
     17 
---> 18 msgStudent(exStudent.getFullName(), printMsg())
<ipython-input-16-618076368e04> in msgStudent(name, function)
     11 def msgStudent(name, function):
     12     print("Hi",name)
---> 13     function() # Calling None object as a function
     14 
     15 exStudent = Student()

TypeError: 'NoneType' object is not callable

To solve this error, let’s follow two solutions we suggest below:

1) Change the name of method in class

The reason of this error is that when you name the function as the name of a attribute, the attribute will be the first priority to access. As a result, you call the attribute as a function, which cause the Error as the example.

You can change the method name: fullname(obj) to getFullName(obj) as shown the code in the below example to fix the error.

Code sample

class Student:
    def __init__(obj):
        obj.fullname = None

    def getFullName(obj):
        return obj.fullname
		
exStudent = Student()
exStudent.fullname = "Robert Collier"
print(exStudent.getFullName())

Output

'Robert Collier'

2) Remove the parentheses ‘()’

When you pass a non-returning function as a parameter of another function, it is a common mistake to add the parenthesis after the function’s name. It means you call the result of the function as a function accidentally.

Remove the parentheses ‘()’ in the msgStudent(exStudent.getFullName(), printMsg()) statement. The alternative statement would be msgStudent(exStudent.getFullName(), printMsg). When you do that, your error will be fixed.

Code sample

class Student:
    def __init__(obj):
        obj.fullname = None

    def getFullName(obj):
        return obj.fullname
		
def printMsg():
    print('Welcome to LearnShareIT')
    
def msgStudent(name, function):
    print("Hi", name)
    function() # Calling None object as a function 
	
exStudent = Student()
exStudent.fullname = "Robert Collier"

msgStudent(exStudent.getFullName(), printMsg) # Remove ... ()

Output:

Hi Robert Collier
Welcome to LearnShareIT

Summary

In conclusion, “TypeError: ‘nonetype’ object is not callable” occurs when you call a None object as a function. The only way to solve the problem is understanding which parameter is an object and which parameter is a function.

Maybe you are interested:

• TypeError: ‘NoneType’ object is not iterable in Python
• TypeError: ‘set’ object is not subscriptable in Python
• TypeError: ‘str’ object does not support item assignment
• TypeError: a bytes-like object is required, not ‘str’ in python

In Python, a specific data type referred to as “NoneType” is used to store “None” value. Python uses the keyword “None” to store the “Null/None” value in a variable. Some functions in Python also return the “None” value, such as the sort() function.

While dealing with a “None” value, “TypeError: NoneType object is not callable” may occur in Python. To resolve this error, various solutions are provided by Python.

This blog will provide a comprehensive guide on resolving the “TypeError: NoneType object is not callable” in Python. This guide contains the following contents:

• Reason 1: Using the Same Name for Function and Variable
• Solution: Rename Variable or Function
• Reason 2: Class Methods and Class Properties Have the Same Name
• Solution: Rename the Class Method or Class Attributes
• Reason 3: Calling None Variable as a Function
• Solution: Removing Parentheses

So, let’s get started!

Reason 1: Using the Same Name for Function and Variable

This “TypeError” occurs when we try to use the same name for a function and variable in a Python program. Here is an example:

The above output shows the “TypeError” because the function “sample” and variable “sample” are initialized with the same name in a program.

Solution: Rename Variable or Function

To fix this error, make sure to rename the function or variable in a program. After renaming the function or variable, re-execute the program to remove the error.

Code:

def sample1():
    return 'True'
sample = None
print(sample1())

In the above code, the user-defined function is renamed from “sample” into “sample1”. After renaming the function name, the function value will be accessed using parentheses.

Output:

The above output verified that the function returns a “None” value.

Reason 2: Class Methods and Class Properties Have the Same Name

The other prominent reason which produces this error in the program is when the user uses the same name for the class property and class method. Here is an example:

The above output, the class method “example”, and the class property/attribute “self.example” have the same name in a program.

Solution: Rename the Class Method or Class Attributes

To rectify this error, rename the method of the class and re-execute the Python script. Here’s an example:

Code:

class sample():
    def __init__(self):
        self.example = None
       
    def value(self):
        return "True"
   
smp = sample()
print(smp.value())

In the above code, the class method name “example” is renamed to “value”. After renaming the method, the program runs successfully without any errors.

Output:

The above output verified that the class method executes the program successfully.

Reason 3: Calling None Variable as a Function

The error also arises when the user calls the none value as if it were a function in a Python program. Below is an example of this error:

The above output displays the “TypeError” because the none value variable is called as a function in Python.

Solution: Removing Parentheses

To resolve this error, you need to remove the parentheses or correct the assignment. Let’s look at the below solutions code:

Code:

value = None
print(value)

In the above code, the “None” value is assigned to the variable “value” in the program. The value is displayed on the screen using the “print()” function.

Output:

This output displays the value of the variable “value“.

Conclusion

The “TypeError: NoneType object is not callable” arises in Python when we try to access a “None” variable as a Function or use the same name for a variable and function, etc. To resolve this error, various solutions are provided, such as renaming functions or variables, renaming class methods, and removing parentheses while accessing variables. This Python article has presented a detailed guide on resolving the “NoneType object is not callable” error using appropriate examples.