In Python, the subscriptable objects, i.e., list, string, dictionary, tuple, etc. are only accessed using square brackets. However, when the built-in methods or functions are accessed using a square bracket, the “built_function_or_method object is not subscriptable” error occurs in Python. To solve this error, Python provides several solutions discussed in this guide. The content of the post is as follows:
- Reason: Use Square Bracket to Call a Builtin Function or Method
- Solution: Use Parentheses Instead of Square Brackets
- Alternate Solution: Use Parentheses to Accessed User-Defined Functions
- Example: Use Parentheses to Pass a List as a Function Argument
Reason: Use Square Bracket to Call a Builtin Function or Method
The main reason which causes this error in the Python program is when a user tries to call a built-in method or function using a square bracket. As we know, calling a function or method is impossible using a square bracket; it will generate a “Not subscriptable” error in Python as shown below:
The above reason snippet shows the “TypeError” when the function is called using a square bracket instead of parentheses.
Solution: Use Parentheses Instead of Square Brackets
To resolve this error, make sure to use parentheses instead of square brackets while calling the built-in method or function in Python. The correct code is shown in the below code block:
list_value = ['python', 'and', 'linux'] list_value.pop(0) print(list_value)
In the above code, the list is created, and the “list.pop()‘ function is used to delete the specific item from the index position “0” of the input list.
The element at the index position “0” has been removed using the “list.pop()” function.
Alternate Solution: Use Parentheses to Accessed User-Defined Functions
The user-defined function is defined in the program using the prefix keyword “def” in Python. To call the user-defined function, we use parentheses instead of the square bracket and store it in a newly created object variable. An example of this solution is shown in the below snippet:
def sample_list(): return ['python', 'ubuntu', 'linux'] list_1 = sample_list() print(list_1)
In the above code, the user-defined function “sample_list” is defined in the program. The function is accessed using parentheses. The return value of the function is kept in a variable named “list_1”.
The value returned by the function is shown successfully on the output without any error.
Example: Use Parentheses to Pass a List as a Function Argument
In the example code given below, the parentheses are used to call the function on the list. Ensure that a list is passed as an argument to a function to avoid an error:
list_value =  list_value.extend(['Python', 'Guide', 'Linux']) print(list_value)
In the above code, an empty list is created at the start of the program. The “list.extend()” function calls on the newly initialized list created inside the function’s parentheses.
The above output shows that the function successfully extended the list (a list passed as an argument to a function) into an empty list.
The error “builtin_function_or_method’ object is not subscriptable” occurs when a user tries to call the built-in method or function using a square bracket. To fix this error, use parentheses instead of the square bracket to access the built-in method or function in Python. Moreover, the brackets cannot be used to call a user-defined function whose solution is also provided. Multiple solutions have been explained in this Python blog post to handle this “builtin_function_or_method’ object is not subscriptable”.