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!

Objects with the value None cannot be called. This is because None values are not associated with a function. If you try to call an object with the value None, you’ll encounter the error “TypeError: ‘nonetype’ object is not callable”.

In this guide, we discuss why this error is raised and what it means. We’ll walk through an example of this error to help you understand how you can solve it in your program.

TypeError: ‘nonetype’ object is not callable

When you call a function, the code inside the function is executed by the Python interpreter.

Only functions can be called. To call a function, you need to specify the name of a function, followed by a set of parentheses. Those parenthesis can optionally contain arguments that are passed through to a function.

Consider the following code:

def show_languages():
	print("Python, Java, C, C++")

show_languages()

First, declare a function called “show_languages”.

On the last line of our code, we call our function. This executes all the code in the block where we declare the “show_languages” function.

Similar to how you cannot call a string, a tuple, or a dictionary, you cannot call a None value. These data types do not respond to a function call because they are not functions. The result of calling a None value is always “TypeError: ‘nonetype’ object is not callable”. 

An Example Scenario

Let’s build a program that reads a file with a leaderboard for a poker tournament and prints out each player’s position on the leaderboard to the console.

We have a file called poker.txt which contains the following:

1: Greg Daniels
2: Lucy Scott
3: Hardy Graham
4: Jenny Carlton
5: Hunter Patterson

We start by writing a function that reads the file with leaderboard information:

def tournament_results():
	with open("poker.txt", "r") as file:
		tournament = file.readlines()
		return tournament

This function opens the “poker.txt” file in read mode and reads its contents into a variable called “tournament”. We return this variable to the main program.

Until we call our function, “tournament_results” will not have a value. So, we’re going to initialize a variable that stores our tournament scores:

tournament_results = None

Now that we’ve initialized this variable, we can move on to the next part of our program. We call our tournament_results() function to get the tournament data. We then use a for loop to print each value to the console:

tournament_results = tournament_results()

for t in tournament_results:
	print(t)

Our for loop prints each line from our file to the console. Let’s run our code and see what happens:

Traceback (most recent call last):
  File "main.py", line 8, in <module>
	tournament_results = tournament_results()
TypeError: 'NoneType' object is not callable

Our code returns an error message.

The Solution

In our code, we have declared two values with the name “tournament_results”: a function and a variable. We first declare our function and then we declare our variable.

When we declare the “tournament_results” variable, we override the function. This means that whenever we reference “tournament_results”, our program will refer to the variable.

This causes a problem when we try to call our function:

tournament_results = tournament_results()

To solve this error, we should rename the variable “tournament_results” to something else:

final_results = None

final_results = tournament_results()

for f in final_results:
	print(f)

We have renamed the “tournament_results” variable to “final_results”. Let’s see whether this solves the error we experienced:

1: Greg Daniels

2: Lucy Scott

3: Hardy Graham

4: Jenny Carlton

5: Hunter Patterson

Our code successfully prints out all of the text in our file. This is because we’re no longer overriding the “tournament_results” with the value None. 

Conclusion

“TypeError: ‘nonetype’ object is not callable” occurs when you try to call a None value as if it were a function.

To solve it, make sure that you do not override the names of any functions with a None value. Now you have the knowledge you need to fix this error like an expert!

“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