Builtin function or method python ошибка

Can’t believe this thread was going on for so long.
You would get this error if you got distracted
and used [] instead of (), at least my case.

Pop is a method on the list data type,
https://docs.python.org/2/tutorial/datastructures.html#more-on-lists

Therefore, you shouldn’t be using pop as if it was a list itself, pop[0].
It’s a method that takes an optional parameter representing an index,
so as Tushar Palawat pointed out in one of the answers that didn’t get approved,
the correct adjustment which will fix the example above is:

listb.pop(0)

If you don’t believe, run a sample such as:

if __name__ == '__main__':
  listb = ["-test"]
  if( listb[0] == "-test"):
    print(listb.pop(0))

Other adjustments would work as well, but it feels as they are abusing the Python language. This thread needs to get fixed, not to confuse users.

Addition,
a.pop() removes and returns the last item in the list.
As a result, a.pop()[0] will get the first character of that
last element. It doesn’t seem that is what the given code snippet
is aiming to achieve.

Functions are blocks of code that work and behave together under a name. Built-in functions have their functionality predefined. To call a built-in function, you need to use parentheses (). If you do not use parentheses, the Python interpreter cannot distinguish function calls from other operations such as indexing on a list object.

Using square brackets instead of parentheses to call a built-in function will raise the “TypeError: ‘builtin_function_or_method’ object is not subscriptable”.

In this tutorial, we will go into detail on the error definition. We will go through an example scenario of raising the error and how to solve it.

TypeError: ‘builtin_function_or_method’ object is not subscriptable

Two parts of the error tell you what has gone wrong. TypeError occurs whenever we try to perform an illegal operation for a specific data type. For example, trying to iterate over a non-iterable object, like an integer will raise the error: “TypeError: ‘int’ object is not iterable“.

The part “‘builtin_function_or_method’ object is not subscriptable” occurs when we try to access the elements of a built-in function, which is not possible because it is a non-subscriptable object. Accessing elements is only suitable for subscriptable objects like strings, lists, dictionaries, and tuples. Subscriptable objects implement the __getitem__() method, non-subscriptable objects do not implement the __getitem__() method.

Let’s look at the correct use of indexing on a string:

string = "Machine Learning"

print(string[0])

Example: Using the Built-in sum Function with Square Brackets

Let’s write a program that defines an array of integers and a variable that stores the sum of the integers in the array. The sum() function calculates the sum of Python container objects, including lists, tuples and dictionaries.

numbers = [10, 4, 2, 5, 7]

total = sum[numbers]

print(total)

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
total = sum[numbers]

TypeError: 'builtin_function_or_method' object is not subscriptable

In this code, we are trying to sum the integers in the array called numbers, but we are using square brackets [] instead of parenthesis (), which tells the Python interpreter to treat sum like a subscriptable object. But indexing is illegal for built-in functions because they are not containers of objects.

Solution

To solve the problem, we replace the square brackets with parentheses after the function name:

numbers = [10, 4, 2, 5, 7]

total = sum(numbers)

print(total)

28

Our code successfully calculated the sum of the integers in the array and printed the sum value to the console.

Summary

Congratulations on reading to the end of this tutorial.

For further reading on not subscriptable errors, go to the articles:

• How to Solve Python TypeError: ‘method’ object is not subscriptable
• How to Solve Python TypeError: ‘Response’ object is not subscriptable

Go to the online courses Python page to learn more about Python for data science and machine learning.

Have fun and happy researching!

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To call a built-in function, you need to use parentheses. Parentheses distinguish function calls from other operations that can be performed on some objects, like indexing.

If you try to use square brackets to call a built-in function, you’ll encounter the “TypeError: ‘builtin_function_or_method’ object is not subscriptable” error. 

In this guide, we talk about what this error means and why you may encounter it. We’ll walk through an example so that you can figure out how to solve the error.

TypeError: ‘builtin_function_or_method’ object is not subscriptable

Only iterable objects are subscriptable. Examples of iterable objects include lists, strings, and dictionaries. Individual values in these objects can be accessed using indexing. This is because items within an iterable object have index values.

Consider the following code:

languages = ["English", "French"]
print(languages[0])

Our code returns “English”. Our code retrieves the first item in our list, which is the item at index position 0. Our list is subscriptable so we can access it using square brackets.

Built-in functions are not subscriptable. This is because they do not return a list of objects that can be accessed using indexing.

The “TypeError: ‘builtin_function_or_method’ object is not subscriptable” error occurs when you try to access a built-in function using square brackets. This is because when the Python interpreter sees square brackets it tries to access items from a value as if that value is iterable.

An Example Scenario

We’re going to build a program that appends all of the records from a list of homeware goods to another list. An item should only be added to the next list if that item is in stock.

Start by defining a list of homeware goods and a list to store those that are in stock:

homewares = [
	{ "name": "Gray Lampshade", "in_stock": True },
	{ "name": "Black Wardrobe", "in_stock": True },
{ "name": "Black Bedside Cabinet", "in_stock": False }
]
in_stock = []

The “in_stock” list is presently empty. This is because we have not yet calculated which items in stock should be added to the list.

Next, we use a for loop to find items in the “homewares” list that are in stock. We’ll add those items to the “in_stock” list:

for h in homewares:
	if h["in_stock"] == True:
		in_stock.append[h]

print(in_stock)

We use the append() method to add a record to the “in_stock” list if that item is in stock. Otherwise, our program does not add a record to the “in_stock” list. Our program then prints out all of the objects in the “in_stock” list.

Let’s run our code and see what happens:

Traceback (most recent call last):
  File "main.py", line 10, in <module>
	in_stock.append[h]
TypeError: 'builtin_function_or_method' object is not subscriptable

Our code returns an error.

The Solution

Take a look at the line of code that Python points to in the error:

We’ve tried to use indexing syntax to add an item to our “in_stock” list variable. This is incorrect because functions are not iterable objects. To call a function, we need to use parenthesis.

We fix this problem by replacing the square brackets with parentheses:

Let’s run our code:

[{'name': 'Gray Lampshade', 'in_stock': True}, {'name': 'Black Wardrobe', 'in_stock': True}]

Our code successfully calculates the items in stock. Those items are added to the “in_stock” list which is printed to the console.

Conclusion

The “TypeError: ‘builtin_function_or_method’ object is not subscriptable” error is raised when you try to use square brackets to call a function.

This error is raised because Python interprets square brackets as a way of accessing items from an iterable object. Functions must be called using parenthesis. To fix this problem, make sure you call a function using parenthesis.

Now you’re ready to solve this common Python error like an expert!