Python make class subscriptable

Python TypeError: ‘int’ object is not subscriptable

In Python, we use Integers to store the whole numbers, and it is not a subscriptable object. If you treat an integer like a subscriptable object, the Python interpreter will raise TypeError: ‘int’ object is not subscriptable.

In this tutorial, we will learn what ‘int’ object is is not subscriptable error means and how to resolve this TypeError in your program with examples.

What is Subscriptable in Python?

“Subscriptable” means that you’re trying to access an element of the object. The elements are usually accessed using indexing since it is the same as a mathematical notation that uses actual subscripts.

How do you make an object Subscriptable?

In Python, any objects that implement the __getitem__ method in the class definition are called subscriptable objects, and by using the __getitem__ method, we can access the elements of the object.

For example, strings, lists, dictionaries, tuples are all subscriptable objects. We can retrieve the items from these objects using indexing.

How to Fix TypeError: ‘int’ object is not subscriptable?

Let us take a small example to read the birth date from the user and slice the day, months and year values into separate lines.

birth_date = int(input("Please enter your birthdate in the format of (mmddyyyy) ")) birth_month = birth_date[0:2] birth_day = birth_date[2:4] birth_year = birth_date[4:8] print("Birth Month:", birth_month) print("Birth Day:", birth_day) print("Birth Year:", birth_year) 

If you look at the above program, we are reading the user birth date as an input parameter in the mmddyy format.

Then to retrieve the values of the day, month and year from the user input, we use slicing and store it into a variable.

When we run the code, Python will raise a TypeError: ‘int’ object is not subscriptable.

Please enter your birthdate in the format of (mmddyyyy) 01302004 Traceback (most recent call last): File "C:\Personal\IJS\Code\main.py", line 3, in birth_month = birth_date[0:2] TypeError: 'int' object is not subscriptable

Solution

In our example, we are reading the birth date as input from the user and the value is converted to an integer.

The integer values cannot be accessed using slicing or indexing, and if we do that, we get the TypeError.

To solve this issue, we can remove the int() conversion while reading the input from the string. So now the birth_date will be of type string, and we can use slicing or indexing on the string variable.

Let’s correct our example and run the code.

birth_date = input("Please enter your birthdate in the format of (mmddyyyy) ") birth_month = birth_date[0:2] birth_day = birth_date[2:4] birth_year = birth_date[4:8] print("Birth Month:", birth_month) print("Birth Day:", birth_day) print("Birth Year:", birth_year) 

Please enter your birthdate in the format of (mmddyyyy) 01302004 Birth Month: 01 Birth Day: 30 Birth Year: 2004

The code runs successfully since the int() conversion is removed from the code, and slicing works perfectly on the string object to extract a day, month and year.

Conclusion

The TypeError: ‘int’ object is not subscriptable error occurs if we try to index or slice the integer as if it is a subscriptable object like list, dict, or string objects.

The issue can be resolved by removing any indexing or slicing to access the values of the integer object. If you still need to perform indexing or slicing on integer objects, you need to first convert that into strings or lists and then perform this operation.

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How to implement a subscriptable class in python (subscriptable class, not subscriptable object)?

A subscriptable class in Python allows an object of that class to be indexed or sliced like a list, tuple, or string. To make a class subscriptable, it must implement the special method __getitem__ .

Method 1: Using __getitem__ method

To implement a subscriptable class in Python, you can use the __getitem__ method. This method allows you to define how instances of your class behave when accessed with the square bracket notation.

Here’s an example implementation of a subscriptable class using __getitem__ :

class Subscriptable: def __init__(self, data): self.data = data def __getitem__(self, index): return self.data[index]

In this example, the Subscriptable class takes a list of data as an argument in its constructor. The __getitem__ method is then used to define how instances of the class behave when accessed with the square bracket notation. In this case, it simply returns the item at the specified index in the data list.

You can then create an instance of the class and access it using the square bracket notation like this:

data = ['a', 'b', 'c'] subscriptable = Subscriptable(data) print(subscriptable[0]) # Output: 'a'

You can also implement more complex behavior in the __getitem__ method. For example, you can add logic to handle out-of-bounds indices:

class SafeSubscriptable: def __init__(self, data): self.data = data def __getitem__(self, index): if index  0 or index >= len(self.data): raise IndexError("Index out of bounds") return self.data[index]

In this example, the SafeSubscriptable class checks if the index is out of bounds and raises an IndexError if it is. Otherwise, it behaves the same as the previous example.

You can then use this class in the same way as the previous example:

data = ['a', 'b', 'c'] subscriptable = SafeSubscriptable(data) print(subscriptable[3]) # Raises IndexError

Using the __getitem__ method is a powerful way to make your classes subscriptable in Python. By defining how instances of your class behave when accessed with the square bracket notation, you can add a lot of flexibility and convenience to your code.

Method 2: Using Collection ABC

To implement a subscriptable class in Python using Collection ABC, you can use the MutableSequence class from the collections.abc module. This class provides a basic framework for creating a mutable sequence, which can be indexed and iterated over.

Here is an example implementation:

from collections.abc import MutableSequence class MyList(MutableSequence): def __init__(self): self._items = [] def __getitem__(self, index): return self._items[index] def __setitem__(self, index, value): self._items[index] = value def __delitem__(self, index): del self._items[index] def insert(self, index, value): self._items.insert(index, value) def __len__(self): return len(self._items)

In this implementation, we define a class MyList that extends MutableSequence . We initialize an empty list _items in the constructor.

Then we define the __getitem__ , __setitem__ , __delitem__ , and insert methods, which are required by MutableSequence . These methods allow us to get, set, delete, and insert items in the list.

Finally, we define the __len__ method, which returns the length of the list.

With this implementation, we can create an instance of MyList and use it like any other list:

my_list = MyList() my_list.append(1) my_list.append(2) my_list.append(3) print(my_list[0]) # 1 print(my_list[1]) # 2 my_list[1] = 4 print(my_list) # [1, 4, 3] del my_list[0] print(my_list) # [4, 3] my_list.insert(1, 5) print(my_list) # [4, 5, 3]

In this example, we create an instance of MyList and add some items to it. We then use the indexing and mutation methods provided by MutableSequence to modify the list.

Overall, using Collection ABC provides a simple and consistent way to implement a subscriptable class in Python.

Method 3: Using collections.abc.Sequence

To implement a subscriptable class in Python using collections.abc.Sequence , you need to define the following methods:

1. __len__(self) : This method returns the length of the sequence.
2. __getitem__(self, index) : This method returns the item at the given index.
3. __setitem__(self, index, value) : This method sets the item at the given index to the given value.
4. __delitem__(self, index) : This method deletes the item at the given index.

Here’s an example code that implements a subscriptable class using collections.abc.Sequence :

from collections.abc import Sequence class MySequence(Sequence): def __init__(self, items): self.items = items def __len__(self): return len(self.items) def __getitem__(self, index): return self.items[index] def __setitem__(self, index, value): self.items[index] = value def __delitem__(self, index): del self.items[index]

With this implementation, you can create an instance of MySequence and access its items using the subscript notation:

seq = MySequence([1, 2, 3, 4, 5]) print(seq[0]) # Output: 1 print(seq[3]) # Output: 4 seq[2] = 10 print(seq[2]) # Output: 10 del seq[1] print(seq[1]) # Output: 3 print(len(seq)) # Output: 4

Note that MySequence also supports slicing and iteration, because collections.abc.Sequence defines default implementations for these methods.

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[Solved] TypeError: method Object is not Subscriptable

Welcome to another module of TypeError in the python programming language. In today’s article, we will be discussing an embarrassing Typeerror that usually gets landed up while we are a beginner to python. The error is named as TypeError: ‘method’ object is not subscriptable Solution.

In this guide, we’ll go through the causes and ultimately the solutions for this TypeError problem.

What are Subscriptable Objects in Python?

Subscriptable objects are the objects in which you can use the [item] method using square brackets. For example, to index a list, you can use the list[1] way.

Inside the class, the __getitem__ method is used to overload the object to make them compatible for accessing elements. Currently, this method is already implemented in lists, dictionaries, and tuples. Most importantly, every time this method returns the respective elements from the list.

Now, the problem arises when objects with the __getitem__ method are not overloaded and you try to subscript the object. In such cases, the ‘method’ object is not subscriptable error arises.

Why do you get TypeError: ‘method’ object is not subscriptable Error in python?

In Python, some of the objects can be used to access the inside elements by using square brackets. For example in List, Tuple, and dictionaries. But what happens when you use square brackets to objects which arent supported? It’ll throw an error.

Let us consider the following code snippet:

names = ["Python", "Pool", "Latracal", "Google"] print(names[0]) int("5")[0]

OUTPUT:- Python TypeError: int object is not subscriptable

This code returns “Python,” the name at the index position 0. We cannot use square brackets to call a function or a method because functions and methods are not subscriptable objects.

Example Code for the TypeError

x = 3 x[0] # example 1 p = True p[0] # example 2 max[2] # example 3

Explanation of the code

1. Here we started by declaring a value x which stores an integer value 3.
2. Then we used [0] to subscript the value. But as integer doesn’t support it, an error is raised.
3. The same goes for example 2 where p is a boolean.
4. In example 3, max is a default inbuilt function which is not subscriptable.

The solution to the TypeError: method Object is not Subscriptable

The only solution for this problem is to avoid using square brackets on unsupported objects. Following example can demonstrate it –

x = 3 print(x) p = True print(p) max([1])

Our code works since we haven’t subscripted unsupported objects.

If you want to access the elements like string, you much convert the objects into a string first. The following example can help you to understand –

x = 3 str(x)[0] # example 1 p = True str(p)[0] # example 2

Also, Read

FAQs

1. When do we get TypeError: ‘builtin_function_or_method’ object is not subscriptable?

Ans:- Let us look as the following code snippet first to understand this.

import numpy as np a = np.array[1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

This problem is usually caused by missing the round parentheses in the np.array line.

It should have been written as:

a = np.array([1,2,3,4,5,6,7,8,9,10])

It is quite similar to TypeError: ‘method’ object is not subscriptable the only difference is that here we are using a library numpy so we get TypeError: ‘builtin_function_or_method’ object is not subscriptable.

Conclusion

The “TypeError: ‘method’ object is not subscriptable” error is raised when you use square brackets to call a method inside a class. To solve this error, make sure that you only call methods of a class using round brackets after the name of the method you want to call.

Now you’re ready to solve this common Python error like a professional coder! Till then keep pythoning Geeks!

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