Ошибка nonetype object has no attribute id

We raise a Python AttributeError when we try to call or access an attribute of an object that does not exist for that object.

This tutorial will go through what an attribute is, what the AttributeError is in detail, and we will go through four examples to learn how to solve the error.

What is a Python AttributeError?

An attribute of an object is a value or a function associated with that object. We can express calling a method of a class as referencing an attribute of a class.

Let’s look at an example of a Python class for the particle electron

class Electron:
    def __init__(self):
        self.charge = -1
        self.mass = 0.51
        self.spin = 1/2
 
    def positron(self):
        self.charge = +1
        return self.charge

We can think of an attribute in Python as a physical attribute of an object. In this example, the fundamental particle, the electron, has physical attributes of charge, mass, and spin. The Electron class has the attributes charge, mass, and spin.

An attribute can also be a function. The function positron() returns the charge of the electron’s anti-particle, the positron.

Data types can have attributes. For example, the built-in data type List has the append() method to append elements to an existing list. Therefore, List objects support the append() method. Let’s look at an example of appending to a list:

a_list = [2, 4, 6]

a_list.append(8)

print(a_list)

Attributes have to exist for a class object or a data type for you to reference it. If the attribute is not associated with a class object or data type, you will raise an AttributeError.

Example #1: Trying to Use append() on a String

Let’s look at an example scenario where we concatenate two strings by appending one string to another.

string1 = "research"

string2 = "scientist"

string1.append(string2)

Using append() is impossible because the string data type does not have the append() method. Let’s run the code to see what happens:

---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
1 string1.append(string2)

AttributeError: 'str' object has no attribute 'append'

Solution

To solve this problem, we need to define a third string. We can then concatenate the two strings using the + symbol and assign the result to the third string. We can concatenate a space between the two strings so that the words do not run together. Let’s look at how the revised code:

string1 = "research"

string2 = "scientist"

string3 = string1 + " " + string2

print(string3)

research scientist

Example #2: Trying to Access an Attribute of a Class that does not exist

Let’s look at an example scenario where we want to access an attribute of a class that does not exist. We can try to create an instance of the class Electron from earlier in the tutorial. Once we have the instance, we can try to use the function get_mass() to print the mass of the electron in MeV.

class Electron:

   def __init__(self):

       self.charge = -1

       self.mass = 0.51

       self.spin = 1/2
  
   def positron(self):

       self.charge = +1

       return self.charge

electron = Electron()

mass = electron.get_mass()

If we try to run the code, we get the following error:

---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
1 mass = electron.get_mass()

AttributeError: 'Electron' object has no attribute 'get_mass'

The Electron class has no attribute called get_mass(). Therefore we raise an AttributeError.

Solution

To solve this, we can do two things. We can add the method to the class and use a try-except statement. First, let’s look at adding the method:

class Electron:
    def __init__(self):
        self.charge = -1
        self.mass = 0.51
        self.spin = 1/2

    def positron(self):
        self.charge = +1
        return self.charge

    def get_mass(self):
            return self.mass
electron = Electron()

mass = electron.get_mass()

print(f' The mass of the electron is {mass} MeV')

 The mass of the electron is 0.51 MeV

Secondly, let’s look at using try-except to catch the AttributeError. We can use try-except statements to catch any error, not just AttributeError. Suppose we want to use a method called get_charge() to get the charge of the electron object, but we are not sure whether the Electron class contains the get_charge() attribute. We can enclose the call to get_charge() in a try-except statement.

class Electron:

    def __init__(self):

        self.charge = -1

        self.mass = 0.51

        self.spin = 1/2

    def positron(self):

        self.charge = +1

        return self.charge

    def get_mass(self):

            return self.mass

electron = Electron()

try:

    charge = electron.get_charge()

except Exception as e:

    print(e)

'Electron' object has no attribute 'get_charge'

Using try-except statements aligns with professional development and makes your programs less prone to crashing.

Example #3: NoneType Object has no Attribute

NoneType means that whatever class or object you are trying to access is None. Therefore, whenever you try to do a function call or an assignment for that object, it will raise the AttributeError: ‘NoneType’ object has no attribute. Let’s look at an example scenario for a specific NoneType attribute error. We will write a program that uses regular expressions to search for an upper case “S” character at the beginning and print the word. We need to import the module re for regular expression matching.

import re

# Search for an upper case "S" character in the beginning of a word then print the word

string = "Research Scientist"

for i in string.split():

    x = re.match(r"bSw+", i)

    print(x.group())

Let’s run the code and see what happens:

---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
      1 for i in string.split():
      2     x = re.match(r"bSw+", i)
      3     print(x.group())
      4 

AttributeError: 'NoneType' object has no attribute 'group'

We raise the AttributeError because there is no match in the first iteration. Therefore x returns None. The attribute group() does not belong to NoneType objects.

Solution

To solve this error, we want to only call group() for the situation where there is a match to the regular expression. We can therefore use the try-except block to handle the AttributeError. We can use continue to skip when x returns None in the for loop. Let’s look at the revised code.

import re

# Search for an upper case "S" character in the beginning of a word then print the word

string = "Research Scientist"
for i in string.split():
    x = re.match(r"bSw+", i)
    try:
        print(x.group())
    except AttributeError:
        continue

Scientist

We can see that the code prints out Scientist, which is the word that has an upper case “S” character.

Example #4: Handling Modules

We can encounter an AttributeError while working with modules because we may call a function that does not exist for a module. Let’s look at an example of importing the math module and calling a function to perform a square root.

import math

number = 9

square_root_number = math.square_root(number)

---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
1 square_root_number = math.square_root(number)

AttributeError: module 'math' has no attribute 'square_root'

The module math does not contain the attribute square_root. Therefore we get an AttributeError.

Solution

To solve this error, you can use the help() function to get the module’s documentation, including the functions that belong to the module. We can use the help function on the math module to see which function corresponds to the square root.

import math

help(math)

  sqrt(x, /)

        Return the square root of x.

The function’s name to return the square root of a number is sqrt(). We can use this function in place of the incorrect function name.

square_root_number = math.sqrt(number)

print(square_root_number)

3.0

The code successfully returns the square root of 9. You can also use help() on classes defined in your program. Let’s look at the example of using help() on the Electron class.

help(Electron)

class Electron(builtins.object)
 |  Methods defined here:
 |  
 |  __init__(self)
 |      Initialize self.  See help(type(self)) for accurate signature.
 |  
 |  get_mass(self)
 |  
 |  positron(self)

The help() function returns the methods defined for the Electron class.

Summary

Congratulations on reading to the end of this tutorial. Attribute errors occur in Python when you try to reference an invalid attribute.

• If the attribute you want for built-in data types does not exist, you should look for an attribute that does something similar. For example, there is no append() method for strings but you can use concatenation to combine strings.
• For classes that are defined in your code, you can use help() to find out if an attribute exists before trying to reference it. If it does not exist you can add it to your class and then create a new instance of the class.
• If you are not sure if a function or value does not exist or if a code block may return a NoneType object, you can wrap the code in a try-except statement. Using a try-except stops your program from crashing if you raise an AttributeError.

For further reading on AttributeError, you can go to the following article: How to Solve Python AttributeError: ‘list’ object has no attribute ‘split’

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

Have fun and happy researching!

Я настроил функцию validate внутри rest_framework_simplejwt так, чтобы при аутентификации пользователя она вызывала сигнал user_logged_in, чтобы я мог видеть, вошел пользователь в систему или нет.

Проблема, с которой я столкнулся, заключается в том, что когда пользователь входит в систему, но вводит неправильные данные для входа, я получаю сообщение об ошибке:

AttributeError at /api/token/
'NoneType' object has no attribute 'id'

Вот полное отслеживание:

Traceback (most recent call last):
  File "C:Users15512anaconda3libsite-packagesdjangocorehandlersexception.py", line 47, in inner
    response = get_response(request)
  File "C:Users15512anaconda3libsite-packagesdjangocorehandlersbase.py", line 181, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "C:Users15512anaconda3libsite-packagesdjangoviewsdecoratorscsrf.py", line 54, in wrapped_view
    return view_func(*args, **kwargs)
  File "C:Users15512anaconda3libsite-packagesdjangoviewsgenericbase.py", line 69, in view
    return self.dispatch(request, *args, **kwargs)
  File "C:Users15512anaconda3libsite-packagesrest_frameworkviews.py", line 509, in dispatch
    response = self.handle_exception(exc)
  File "C:Users15512anaconda3libsite-packagesrest_frameworkviews.py", line 469, in handle_exception
tokens.py", line 176, in for_user
    user_id = getattr(user, api_settings.USER_ID_FIELD)
AttributeError: 'NoneType' object has no attribute 'id'

Вот моя функция валидации :

class CustomTokenObtainPairSerializer(TokenObtainPairSerializer):

    def validate(self, attrs):
        authenticate_kwargs = {
            self.username_field: attrs[self.username_field],
            "password": attrs["password"],
        }
        try:
            authenticate_kwargs["request"] = self.context["request"]
        except KeyError:
            pass
        user = authenticate(**authenticate_kwargs)
        tokens = RefreshToken.for_user(user)
        user_logged_in.send(sender=user.__class__, request=self.context['request'], user=user)

        if not api_settings.USER_AUTHENTICATION_RULE(user):
            raise exceptions.AuthenticationFailed(
                self.error_messages["no_active_account"],
                "no_active_account",
            )

        return {
            'refresh': str(tokens),
            'access': str(tokens.access_token),
            'user': str(user),
        }

Это функция, которая обрабатывает вход/аутентификацию пользователя

Вернуться на верх

1

Discord Bot

31.12.2020, 18:40. Показов 3377. Ответов 1

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@bot.command(pass_context = True)
async def createvoicechannels(ctx):
    role = discord.utils.get(ctx.channel.guild.roles, name = f"{change_1_letter(ctx.channel.category.name, '-', ' ')}")
    for i in range(0, 20):
        role2 = discord.utils.get(ctx.guild.roles, name = "l-Пати-#{i}-l")
        overwrites = {
        ctx.channel.guild.default_role: discord.PermissionOverwrite(read_messages = False),
        ctx.channel.guild.me: discord.PermissionOverwrite(read_messages = True),
        role: discord.PermissionOverwrite(read_messages = True),
        role2: discord.PermissionOverwrite(read_messages = True)}
        await ctx.channel.guild.create_voice_channel(name = f"l-Пати-#{i}-l", category = ctx.channel.category, overwrites = overwrites)

Ignoring exception in command createvoicechannels:
Traceback (most recent call last):
  File "C:UsersplaysAppDataLocalProgramsPythonPython38-32libsite-packagesdiscordextcommandscore.py", line 83, in wrapped
    ret = await coro(*args, **kwargs)
  File "C:UsersplaysOneDriveРабочий столPythonbot2.py", line 59, in createvoicechannels
    await ctx.channel.guild.create_voice_channel(name = f"l-Пати-#{i}-l", category = ctx.channel.category, overwrites = overwrites)
  File "C:UsersplaysAppDataLocalProgramsPythonPython38-32libsite-packagesdiscordguild.py", line 888, in create_voice_channel
    data = await self._create_channel(name, overwrites, ChannelType.voice, category, reason=reason, **options)
  File "C:UsersplaysAppDataLocalProgramsPythonPython38-32libsite-packagesdiscordguild.py", line 771, in _create_channel
    'id': target.id
AttributeError: 'NoneType' object has no attribute 'id'

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "C:UsersplaysAppDataLocalProgramsPythonPython38-32libsite-packagesdiscordextcommandsbot.py", line 892, in invoke
    await ctx.command.invoke(ctx)
  File "C:UsersplaysAppDataLocalProgramsPythonPython38-32libsite-packagesdiscordextcommandscore.py", line 797, in invoke
    await injected(*ctx.args, **ctx.kwargs)
  File "C:UsersplaysAppDataLocalProgramsPythonPython38-32libsite-packagesdiscordextcommandscore.py", line 92, in wrapped
    raise CommandInvokeError(exc) from exc
discord.ext.commands.errors.CommandInvokeError: Command raised an exception: AttributeError: 'NoneType' object has no attribute 'id'

__________________
Помощь в написании контрольных, курсовых и дипломных работ, диссертаций здесь

0

Мне удалось перейти к седьмой главе книги «Разработка через тестирование на Python».

Я просмотрел все темы об одних и тех же ошибках в Google, но объяснения отличаются от моего теста. Поэтому я изо всех сил пытаюсь понять, что не так с кодом ниже. Я понимаю что

AttributeError: 'NoneType' object has no attribute 'id'

говорит мне, 'id' не определен. Но я не знаю, где это исправить в Джанго.

Также для

self.assertEqual(Item.objects.count(), 1)
AssertionError: 0 != 1,

Я не знаю, где искать.

(sup) [email protected]:~/sup1/superlists$ sudo python3 manage.py test lists
Creating test database for alias 'default'...
System check identified no issues (0 silenced).

======================================================================
ERROR: test_redirects_after_POST (lists.tests.NewListTest)
----------------------------------------------------------------------

Traceback (most recent call last):
  File "/home/tim/sup1/superlists/lists/tests.py", line 93, in test_redirects_after_POST
    self.assertRedirects(response, f'/lists/{new_list.id}/')
AttributeError: 'NoneType' object has no attribute 'id'

======================================================================
FAIL: test_can_save_a_POST_request (lists.tests.NewListTest)
----------------------------------------------------------------------

Traceback (most recent call last):
  File "/home/tim/sup1/superlists/lists/tests.py", line 87, in test_can_save_a_POST_request
    self.assertEqual(Item.objects.count(), 1)
AssertionError: 0 != 1

MODELS.PY

from django.db import models

class List(models.Model):
    pass

class Item(models.Model):
    text = models.TextField(default='')
    list = models.ForeignKey(List, default='', null=True, blank=True, on_delete = models.CASCADE)

TESTS.PY

from django.template.loader import render_to_string
from django.urls import resolve, reverse_lazy
from django.test import TestCase
from django.http import HttpRequest

from lists.views import home_page
from lists.models import Item, List

class HomePageTest(TestCase):

    def test_uses_home_template(self):
        response = self.client.get('/')
        self.assertTemplateUsed(response, 'home.html')

    def test_displays_all_list_items(self):
        Item.objects.create(text='itemey 1')
        # Item.objects.create(text='itemey 2')

        response = self.client.get('/')

        self.assertIn('item', response.content.decode())
        # self.assertIn('itemey 2', response.content.decode())

    def test_only_saves_items_when_necessary(self):
        self.client.get('/')
        self.assertEqual(Item.objects.count(), 0)


class ListViewTest(TestCase):

    def test_uses_list_template(self):
        list_ = List.objects.create()
        response = self.client.get(f'/lists/{list_.id}/')
        self.assertTemplateUsed(response, 'list.html')

    def test_displays_only_items_for_that_list(self):
        correct_list = List.objects.create()
        Item.objects.create(text='item', list=correct_list)
        # Item.objects.create(text='itemey 2', list=correct_list)

        response = self.client.get(f'/lists/{correct_list.id}/')

        self.assertContains(response, 'item')
        # self.assertContains(response, 'itemey 2')


    def test_passes_correct_list_to_template(self):
        correct_list = List.objects.create()
        response = self.client.get(f'/lists/{correct_list.id}/')
        self.assertEqual(response.context['list'], correct_list)


class ListAndItemModelsTest(TestCase):

    def test_saving_and_retrieving_items(self):
        list_ = List()
        list_.save()

        first_item = Item()
        first_item.text = 'The first (ever) list item'
        first_item.list = list_
        first_item.save()

        second_item = Item()
        second_item.text = 'Item the second'
        second_item.list = list_
        second_item.save()

        saved_list = List.objects.first()
        self.assertEqual(saved_list, list_)

        saved_items = Item.objects.all()
        self.assertEqual(saved_items.count(), 2)

        first_saved_item = saved_items[0]
        second_saved_item = saved_items[1]
        self.assertEqual(first_saved_item.text, 'The first (ever) list item')
        self.assertEqual(first_saved_item.list, list_)
        self.assertEqual(second_saved_item.text, 'Item the second')
        self.assertEqual(second_saved_item.list, list_)

class NewListTest(TestCase):

    def test_can_save_a_POST_request(self):
        self.client.post('lists/new', {'item_text': 'A new list item'})
        new_item = Item.objects.first()
        self.assertEqual(Item.objects.count(), 1)
        self.assertEqual(new_item.text, 'A new list item')

    def test_redirects_after_POST(self):
        response = self.client.post('/lists/new', data={'item_text': 'A new list item'})
        new_list = List.objects.first()
        self.assertRedirects(response, f'/lists/{new_list.id}/')

class NewItemTest(TestCase):

    def test_can_save_a_POST_request_to_an_existing_list(self):
        correct_list = List.objects.create()

        self.client.post(
            f'/lists/{correct_list.id}/add_item',
            data={'item_text': 'A new item for an existing list'}
        )

        self.assertEqual(Item.objects.count(), 1)
        new_item = Item.objects.first()
        self.assertEqual(new_item.text, 'A new item for an existing list')
        self.assertEqual(new_item.list, correct_list)

    def test_redirects_to_list_view(self):
        correct_list = List.objects.create()
        response = self.client.post(
            f'/lists/{correct_list.id}/add_item',
            data={'item_text': 'A new item for an existing list'}
        )

        self.assertRedirects(response, f'/lists/{correct_list.id}/')

VIEWS.PY

from django.shortcuts import redirect, render
# from django.http import HttpResponse
from lists.models import Item, List

def home_page(request):
    if request.method == 'POST':
        Item.objects.create(text=request.POST['item_text'])
        return redirect('/')
    items = Item.objects.all()
    return render(request, 'home.html')

def view_list(request, list_id):
    list_ = List.objects.get()
    return render(request, 'list.html', {'list': list_})

def new_list(request):
    list_ = List.objects.create()
    Item.objects.create(text=request.POST['item_text'], list=list_)
    return redirect(f'/lists/{list.id}/')

def add_item(request, list_id):
    list_ = List.objects.get(id=list_id)
    Item.objects.create(text=request.POST['item_text'], list=list_)
    return redirect(f'/lists/{list_.id}/')

SUPERLIST — URLS.PY

from django.urls import path, re_path, include
from lists import views as list_views
from lists import urls as list_urls

urlpatterns = [
    #path('admin/', admin.site.urls),
    re_path('^$', list_views.home_page, name="home"),
    path('lists/', include(list_urls)),
    re_path('^lists/new/$', list_views.new_list, name="new_list"),
    re_path('^lists/(d+)/$', list_views.view_list, name="view_list"),
    re_path('^lists/(d+)/add_item$', list_views.add_item, name="add_item"),
]

СПИСОК — URLS.PY

#from django.contrib import admin
from django.urls import path, re_path
from lists import views

urlpatterns = [
    #path('admin/', admin.site.urls),
    re_path('^new/$', views.new_list, name="new_list"),
    re_path('^(d+)/$', views.view_list, name="view_list"),
    re_path('^(d+)/add_item$', views.add_item, name="add_item"),
]

home.html

<html>
  <head>
    <title>To-Do lists</title>
  </head>
  <body>
    <h1>Your To-Do list</h1>
    <form method="POST" action="/lists/new">
      <input name="item_text" id="id_new_item" placeholder="Enter a to-do item" />
      {% csrf_token %}
    </form>
  </body>
</html>

list.html

{% extends 'home.html' %}
<body>
  <h1>Start a new To-Do list</h1>
  <form method="POST" action="/lists/{{ list.id }}/add_item">
    <input name="item_text" id="id_new_item" placeholder="Enter a to-do item" />
    {% csrf_token %}
  </form>
  <table id="id_list_table">
    {% for item in list.item_set.all %}
      <tr><td>{{ forloop.counter }}: {{ item.text }}</td></tr>
    {% endfor %}
  </table>
</body>

Я пытаюсь сохранить пользовательский ввод и убедиться, что страницы перенаправляются правильно, но пока не достигли большого успеха.

Introduction

Problem: How to solve “AttributeError: ‘NoneType’ object has no attribute ‘something’ “?

An AttributeError is raised in Python when you attempt to call the attribute of an object whose type does not support the method. For example, attempting to utilize the append() method on a string returns an AttributeError as lists use the append() function and strings don’t support it. 

Example:

# A set of strings
names = {"John", "Rashi"}
names.extend("Chris")
print(names)

Output:

Traceback (most recent call last):
  File "C:UsersSHUBHAM SAYONPycharmProjectsFinxerErrorsAttributeError - None Type Object.py", line 3, in <module>
    names.extend("Chris")
AttributeError: 'set' object has no attribute 'extend'

Hence, if you attempt to reference a value or function not related to a class object or data type, it will raise an AttributeError.

AttributeError:’NoneType’ object has no attribute ‘something’

Different reasons raise AttributeError: 'NoneType' object has no attribute 'something'. One of the reasons is that NoneType implies that instead of an instance of whatever Class or Object that you are working with, in reality, you have got None. It implies that the function or the assignment call has failed or returned an unforeseen outcome. 

Let’s have a look at an example that leads to the occurrence of this error.

Example 1:

# Assigning value to the variable 
a = None
print(a.something)

Output:

Traceback (most recent call last):
  File "C:UsersSHUBHAM SAYONPycharmProjectsFinxerErrorsAttributeError - None Type Object.py", line 3, in <module>
    print(a.something)
AttributeError: 'NoneType' object has no attribute 'something'

Hence, AttributeError: ‘NoneType’ object has no attribute ‘something’ error occurs when the type of object you are referencing is None.  It can also occur when you reference a wrong function instead of the function used in the program.

Example:

# A function to print numbers
def fun(x):
    if x <= 10:
        x = x + 1
    return x


a = fun(5)
# Calling the function that does not exist
print(a.foo())

Output:

Traceback (most recent call last):
  File "C:UsersSHUBHAM SAYONPycharmProjectsFinxerErrorsAttributeError - None Type Object.py", line 10, in <module>
    print(a.foo())
AttributeError: 'int' object has no attribute 'foo'

How to check if the operator is Nonetype?

Since this AttributeError revolves around the NoneType object, hence it is of primary importance to identify if the object referred has a type None. Thus, you can check if the operator is Nonetype with the help of the “is” operator. It will return True if the object is of the NoneType and return False if not.

Example:

x = None
if x is None:
    print("The value is assigned to None")
else:
    print(x)

Output:

The value is assigned to None

Now that you know how AttributeError: ‘NoneType’ object has no attribute ‘something’ gets raised let’s look at the different methods to solve it.

#Fix 1: Using if and else statements

You can eliminate the AttributeError: 'NoneType' object has no attribute 'something' by using the- if and else statements. The idea here is to check if the object has been assigned a None value.  If it is None then just print a statement stating that the value is Nonetype which might hamper the execution of the program.

Example:

x1 = None
if x1 is not None:
    x1.some_attribute = "Finxter"
else:
    print("The type of x1 is ", type(x1))

Output:

The type of x1 is  <class 'NoneType'>

#Fix 2: Using try and except Blocks

You can also use the exception handling (try and except block) to solve the AttributeError: 'NoneType' object has no attribute 'something'.

Example:

# A function to print numbers
def fun(x):
    if x <= 10:
        x = x + 1
    return x


a = fun(5)
# Using exception handling (try and except block)
try:
    print(a)
    # Calling the function that does not exist
    print(a.foo())

except AttributeError as e:
    print("The value assigned to the object is Nonetype")

Output:

6
The value assigned to the object is Nonetype

Quick Review

Now that we have gone through the ways to fix this AttributeError, let’s go ahead and visualize a few other situations which lead to the occurrence of similar attribute errors and then solve them using the methods we learned above.

1. ‘NoneType’ Object Has No Attribute ‘Group’

import re
# Search for an upper case "S" character in the beginning of a word, and print the word:
txt = "The rain in Spain"
for i in txt.split():
    x = re.match(r"bSw+", i)
    print(x.group())

Output:

Traceback (most recent call last):
  File "D:/PycharmProjects/Errors/attribute_error.py", line 9, in <module>
    print(x.group())
AttributeError: 'NoneType' object has no attribute 'group'

The code encounters an attribute error because in the first iteration it cannot find a match, therefore x returns None. Hence, when we try to use the attribute for the NoneType object, it returns an attribute error.

Solution: Neglect group() for the situation where x returns None and thus does not match the Regex. Therefore use the try-except blocks such that the attribute error is handled by the except block. 

import re
txt = "The rain in Spain"
for i in txt.split():
    x = re.match(r"bSw+", i)
    try:
        print(x.group())
    except AttributeError:
        continue

# Output : Spain

2. Appending list But error ‘NoneType’ object has no attribute ‘append’

li = [1, 2, 3, 4]
for i in range(5):
    li = li.append(i)
print(li)

Output:

Traceback (most recent call last):
  File "C:UsersSHUBHAM SAYONPycharmProjectsFinxerErrorsAttributeError - None Type Object.py", line 3, in <module>
    li = li.append(i)
AttributeError: 'NoneType' object has no attribute 'append'

Solution:

When you are appending to the list as i = li.append(i) you are trying to do an inplace operation which modifies the object and returns nothing (i.e. None). In simple words, you should not assign the value to the li variable while appending, it updates automatically. This is how it should be done:

li = [1, 2, 3, 4]
for i in range(5):
    li.append(i)
print(li)

# output: [1, 2, 3, 4, 0, 1, 2, 3, 4]

Conclusion

To sum things up, there can be numerous cases wherein you wil encounter an attribute error of the above type. But the underlying reason behind every scenario is the same, i.e., the type of object being referenced is None. To handle this error, you can try to rectify the root of the problem by ensuring that the object being referenced is not None. You may also choose to bypass the error based on the requirement of your code with the help of try-cath blocks.

I hope this article helped you to gain a deep understanding of attribute errors. Please stay tuned and subscribe for more interesting articles and discussions.

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