How to Fix – SyntaxError: can’t assign to function

In Python, a function is a block of code that performs a specific task. Functions are defined using the def keyword followed by the function name and parentheses. Sometimes, you may encounter a SyntaxError with the message “can’t assign to function call”. This error occurs when you try to assign a value to a function call.

Understanding the Error

In Python, a function call is a way to execute a function that has been defined in the code. It is done by using the function name followed by parentheses, which may contain arguments that are passed to the function. Depending upon the type of function, the function can return a value or None.

So, a function call is used to execute a function and get some resulting value. Now, if you try to assign a value to a function call, you’ll get a SyntaxError. Let’s look at an example.

def my_function():
    print("Hello, folks!")

my_function() = "some value"

Output:

  Cell In[13], line 4
    my_function() = "some value"
    ^
SyntaxError: cannot assign to function call

Here, we created a function, my_function() that prints a message when called and doesn’t return any value (it returns None). We then try to assign a value (the string, “some value”) to the function call itself and we get SyntaxError: cannot assign to function call.

A function call is not a variable that you can use to store or assign value and thus we get this error.

Fixing the Error

Depending upon your exact use case you can fix this error in the following ways –

1) Use a variable to store the value

You can use a different variable to store the value that you’re trying to store.

def my_function():
    print("Hello, folks!")

a = "some value"

Here, we use the variable a to store the string value “some value”. Notice that we did not get any errors here.

2) Use == if you’re trying to check for equality

A common scenario in which this error occurs is that people use = (which is the assignment operator) in place of == (the equality operator) and thus run into this error.

Often times when a function returns a value, you might want to compare it with some other value. In this case, you need to use the equality operator == which checks whether the two values are equal or not.

Let’s look at an example.

def add(a, b):
    return a+b

# check if add(2, 3) is equal to 5
add(2, 3) == 5

Output:

True

Here, we created a function add() that takes two parameters and returns their sum. We then call the add function with pass 2 and 3 as parameters and compare the return value with 5 (which is the sum of 2 and 3). In this case, we do not get an error because we are using the == operator to check for equality.

If you instead use the assignment operator, =, you’ll get an error because assigning a value to a function call is not allowed (and it doens’t make any snense to do so).

Conclusion

In conclusion, the “SyntaxError: cannot assign to function call” error in Python occurs when you try to assign a value to a function call, which is not allowed in Python. To fix this error, you need to make sure that you are assigning the value to a variable and not to a function call. Additionally, you should check if you’re using = in place of == when comparing the result of a function call to a value. By following these steps, you should be able to resolve this error and continue with your Python programming.

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