typeerror 'nonetype' object does not support item assignment python

• About Jason Ross

TypeError: 'NoneType' object does not support item assignment

• software development

This is an error that turns up occasionally when you're developing code in Python. It started happening in some code I was working on recently, and all of the articles I found when I was looking for the cause said the same thing; that you're trying to assign something to a value that's None . Probably something with an index or key, like a list or dictionary.

This didn't seem to match what I saw in my system at the time, but after looking much more closely it was right, although not for obvious reasons.

I wrote some code to duplicate the error, below:

Running this gave the following output:

This is a much more modern Python interpreter than the one I was using when I first saw the error - the original was reporting the error on line 32:

That was even more confusing, because details was declared and defined here, and make_details() should have been returning a value.

So, it looked like the error reporting in the Python interpreter was, shall we say, vague. The exception was detected at line 32 (above), but it was actually generated somewhere further down the call stack, presumably inside the make_details() function.

Thankfully, the error reporting in Python has improved over time, and line 11 is where the error is detected, even though really it's a symptom, not the actual problem.

The real problem is line 10:

It might not be immediately obvious, but dict.update() in an in-place function, which changes result during the call. Because of this it returns None , which is the actual cause of the problem.

Changing this line to:

fixes the problem.

This problem was one where the answer on the internet was correct, but the cause was harder to find in the code. A simple mistake, where the result of a function that returns None was assigned to a variable, deleted a valid dictionary. This made the following assignment to an indexed value invalid, which is what the error described.

The original code reported the error as occurring in the wrong place, where it was first encountered instead of where it was thrown. If there's nothing else to learn from this, it's that older versions of Python's error detection weren't always great, and so you should always use the newest version you can. Trust me, it'll save you time by at least getting you closer to the source of the problems.

I'm Jason Ross, a software architect and full-stack developer based in Calgary, Alberta, Canada. This is my portfolio site for my professional activities and articles.

I design and build software systems. Systems that provide value to you and your customers as quickly as possible.

I use various methods to automate every part of the process from development and building to deployment and integration testing.

I have an engineering background and I'm a  Chartered Engineer but I now design and write software mostly in C#, Python and C++ on both Windows and Linux, usually with SQL databases, although I've also developed with a few other languages.

If you need any help with your current project, or with a new one, please feel free to contact me.

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Typeerror: nonetype object does not support item assignment

When working with Python projects, we may come across an error that reads “Typeerror: nonetype object does not support item assignment” .

At first glance, this error message can seem cryptic and frustrating. However, it’s actually a helpful clue that points toward the root of the problem.

In this guide, we’ll explore the causes of this error as well as provide practical examples of how to resolve it.

By the end of this guide, we’ll have a better understanding of how to prevent and fix this error in Python.

What is Typeerror: nonetype object does not support item assignment?

The Python error TypeError: ‘NoneType’ object does not support item assignment occurs means that we are trying to assign a value to an object that has a value of None (or null in other programming languages).

Moreover, None is a special value that represents the absence of a value.

Thus it is often used as a default value for function arguments or to indicate that a variable has not been initialized.

Take a look at the next section on how this error occurs…

How to reproduce Typeerror: nonetype object does not support item assignment

Here’s an example code snippet that could produce this error:

In this code, we have a variable x that has not been assigned a value. Its value will be None by default.

Therefore if we try to assign a value to x[0] , you will get a TypeError because you cannot assign a value to an index of None.

Now let’s find the possible factors why and when we can get this error. Hence you might consider in finding solutions.

When do we get this error?

These are the common possible causes when we got the TypeError: ‘NoneType’ object does not support item assignment.

• Trying to assign a value to a variable that has not been initialized or is set to None.
• Using the wrong data type in an operation that requires a mutable object, such as a list or dictionary.
• Calling a function that returns None and trying to perform an item assignment on the result.
• Accessing an object that does not exist, which results in None.
• Overwriting a variable with a function that returns None, causing the variable to become None.
• Using the wrong variable name or referencing the wrong object in a function call.

This time let’s figure out what are the solutions to this error…

How to fix nonetype object does not support item assignment

Here are the possible solutions you can try in fixing the error nonetype object does not support item assignment .

Solution 1: Verify why the variable is assigned to the value None

The first way to fix the error is to ensure why the variable is assigned to None.

Meanwhile, if we assigned a mutable collection of objects (list, set, array, etc.) in a variable it will definitely fix the error.

For example:

[10, 20, 30]

Solution 2: Skip assigning the value using the index if variable is None

In this solution, we should avoid assigning the value using the index, when the variable is assigned to None.

In short, accessing value with an index is pointless.

We should do this way instead:

Solution 3: Create a list with a value assigned to None

Create a list with values assigned to when a variable is assigned to None needs to store values in the variable.

Moreover, the index should be available in the list. Wherein the list assigned to the value None is changeable by adding values to the index.

[5, None, None, None, None, None, None, None, None, None]

Anyway, we also have a solution for Typeerror series objects are mutable thus they cannot be hashed errors, you might encounter.

To conclude, Typeerror: nonetype object does not support item assignment occurs when we are trying to assign a value to an object which has a value of None.

To fix this error, we need to make sure that the variable we are trying to access has a valid value before trying to assign an item to it.

I think that’s all for this guide. We hope you have learned and we helped you fix your error.

Thank you for reading! 😊

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OpenCV: Resolving NoneType errors

by Adrian Rosebrock on December 26, 2016

Each week I receive and respond to at least 2-3 emails and 3-4 blog post comments regarding NoneType errors in OpenCV and Python.

For beginners, these errors can be hard to diagnose — by definition they aren’t very informative.

Since this question is getting asked so often I decided to dedicate an entire blog post to the topic.

While NoneType errors can be caused for a nearly unlimited number of reasons, in my experience, both as a computer vision developer and chatting with other programmers here on PyImageSearch, in over 95% of the cases, NoneType errors in OpenCV are caused by either:

• An invalid image path passed to cv2.imread .
• A problem reading a frame from a video stream/video file via cv2.VideoCapture and the associated .read method.

To learn more about NoneType errors in OpenCV (and how to avoid them), just keep reading .

Looking for the source code to this post?

In the first part of this blog post I’ll discuss exactly what NoneType errors are in the Python programming language.

I’ll then discuss the two primary reasons you’ll run into NoneType errors when using OpenCV and Python together.

Finally, I’ll put together an actual example that not only causes a NoneType error, but also resolves it as well.

What is a NoneType error?

When using the Python programming language you’ll inevitably run into an error that looks like this:

Where something can be replaced by whatever the name of the actual attribute is.

We see these errors when we think we are working with an instance of a particular Class or Object, but in reality we have the Python built-in type None .

As the name suggests, None represents the absence of a value, such as when a function call returns an unexpected result or fails entirely.

Here is an example of generating a NoneType error from the Python shell:

Here I create a variable named foo and set it to None .

I then try to set the bar attribute of foo to True , but since foo is a NoneType object, Python will not allow this — hence the error message.

Two reasons for 95% of OpenCV NoneType errors

When using OpenCV and Python bindings, you’re bound to come across NoneType errors at some point.

In my experience, over 95% of the time these NoneType errors can be traced back to either an issue with cv2.imread or cv2.VideoCapture .

I have provided details for each of the cases below.

Case #1: cv2.imread

If you are receiving a NoneType error and your code is calling cv2.imread , then the likely cause of the error is an invalid file path supplied to cv2.imread .

The cv2.imread function does not explicitly throw an error message if you give it an invalid file path (i.e., a path to a nonexistent file). Instead, cv2.imread will simply return None .

Anytime you try to access an attribute of a None image loaded from disk via cv2.imread you’ll get a NoneType error.

Here is an example of trying to load a nonexistent image from disk:

As you can see, cv2.imread gladly accepts the image path (even though it doesn’t exist), realizes the image path is invalid, and returns None . This is especially confusing for Python programmers who are used to these types of functions throwing exceptions.

As an added bonus, I’ll also mention the AssertionFailed exception.

If you try to pass an invalid image (i.e., NoneType image) into another OpenCV function , Python + OpenCV will complain that the image doesn’t have any width, height, or depth information — and how could it, the “image” is a None object after all!

Here is an example of an error message you might see when loading a nonexistent image from disk and followed by immediately calling an OpenCV function on it:

These types of errors can be harder to debug since there are many reasons why an AssertionError could be thrown. But in most cases, your first step should be be ensuring that your image was correctly loaded from disk.

A final, more rare problem you may encounter with cv2.imread is that your image does exist on disk, but you didn’t compile OpenCV with the given image I/O libraries installed.

For example, let’s say you have a .JPEG file on disk and you knew you had the correct path to it.

You then try to load the JPEG file via cv2.imread and notice a NoneType or AssertionError .

How can this be?

The file exists!

In this case, you likely forgot to compile OpenCV with JPEG file support enabled.

In Debian/Ubuntu systems, this is caused by a lack of libjpeg being installed.

For macOS systems, you likely forgot to install the jpeg library via Homebrew.

To resolve this problem, regardless of operating system, you’ll need to re-compile and re-install OpenCV. Please see this page for more details on how to compile and install OpenCV on your particular system.

Case #2: cv2.VideoCapture and .read

Just like we see NoneType errors and AssertionError exceptions when using cv2.imread , you’ll also see these errors when working with video streams/video files as well.

To access a video stream, OpenCV uses the cv2.VideoCapture which accepts a single argument, either:

• A string representing the path to a video file on disk.
• An integer representing the index of a webcam on your computer.

Working with video streams and video files with OpenCV is more complex than simply loading an image via cv2.imread , but the same rules apply.

If you try to call the .read method of an instantiated cv2.VideoCapture (regardless if it’s a video file or webcam stream) and notice a NoneType error or AssertionError , then you likely have a problem with either:

• The path to your input video file (it’s probably incorrect).
• Not having the proper video codecs installed, in which case you’ll need to install the codecs, followed by re-compiling and re-installing OpenCV (see this page for a complete list of tutorials).
• Your webcam not being accessible via OpenCV. This could be for any number of reasons, including missing drivers, an incorrect index passed to cv2.VideoCapture , or simply your webcam is not properly attached to your system.

Again, working with video files is more complex than working with simple image files, so make sure you’re systematic in resolving the issue.

First, try to access your webcam via a separate piece of software than OpenCV.

Or, try to load your video file in a movie player.

If both of those work, you likely have a problem with your OpenCV install.

Otherwise, it’s most likely a codec or driver issue.

An example of creating and resolving an OpenCV NoneType error

To demonstrate a NoneType error in action I decided to create a highly simplified Python + OpenCV script that represents what you might see elsewhere on the PyImageSearch blog.

Open up a new file, name it display_image.py , and insert the following code:

All this script does is:

• Parse command line arguments.
• (Attempts to) load an image from disk.
• Prints the width, height, and depth of the image to the terminal.
• Displays the image to our screen.

For most Python developers who are familiar with the command line, this script won’t give you any trouble.

But if you’re new to the command line and are unfamiliar/uncomfortable with command line arguments, you can easily run into a NoneType error if you’re not careful.

How, you might say?

The answer lies in not properly using/understanding command line arguments.

Over the past few years of running this blog, I’ve seen many emails and blog post comments from readers who are trying to modify the .add_argument function to supply the path to their image file.

DON’T DO THIS — you don’t have to change a single line of argument parsing code.

Instead, what you should do is spend the next 10 minutes reading through this excellent article that explains what command line arguments are and how to use them in Python:

https://pyimagesearch.com/2018/03/12/python-argparse-command-line-arguments/

This is required reading if you expect to follow tutorials here on the PyImageSearch blog.

Working with the command line, and therefore command line arguments, are a big part of what it means to be a computer scientist — a lack of command line skills is only going to harm you . You’ll thank me later.

Going back to the example, let’s check the contents of my local directory:

As we can see, I have two files:

• display_image.py : My Python script that I’ll be executing shortly.
• jemma.png : The photo I’ll be loading from disk.

If I execute the following command I’ll see the jemma.png image displayed to my screen, along with information on the dimensions of the image:

However, let’s try to load an image path that does not exist:

Sure enough, there is our NoneType   error.

In this case, it was caused because I did not supply a valid image path to cv2.imread  .

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In this blog post I discussed NoneType   errors and AssertionError   exceptions in OpenCV and Python.

In the vast majority of these situations, these errors can be attributed to either the cv2.imread   or cv2.VideoCapture   methods.

Whenever you encounter one of these errors,  make sure you can load your image/read your frame before continuing. In over 95% of circumstances, your image/frame was not properly read.

Otherwise, if you are using command line arguments and are unfamiliar with them, there is a chance that you aren’t using them properly. In that case, make sure you educate yourself by reading this tutorial on command line arguments — you’ll thank me later.

Anyway, I hope this tutorial has helped you in your journey to OpenCV mastery!

If you’re just getting started studying computer vision and OpenCV, I would highly encourage you to take a look at my book,  Practical Python and OpenCV , which will help you grasp the fundamentals.

Otherwise, make sure you enter your email address in the form below to be notified when future blog posts and tutorials are published!

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About the Author

Hi there, I’m Adrian Rosebrock, PhD. All too often I see developers, students, and researchers wasting their time, studying the wrong things, and generally struggling to get started with Computer Vision, Deep Learning, and OpenCV. I created this website to show you what I believe is the best possible way to get your start.

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33 responses to: opencv: resolving nonetype errors.

December 26, 2016 at 12:17 pm

Great article. If writing production code, one should be kind enough to have some basic tests for inputs. I was kind of puzzled before I tested, if the image file could be opened. OpenCV has many very not descriptive errors

December 27, 2016 at 6:40 am

Agreed — writing tests, especially when developing production level OpenCV + Python applications is hugely important.

December 26, 2016 at 6:56 pm

thanks mr for imformation

December 27, 2016 at 3:04 pm

A simple test can also help in some cases where a multi-threaded frame from a camera is not collected correctly, or an image is not ready.

image = cv2.imread(path) # from file # Check that it was a valid image, otherwise try again if (image == None): continue

frame = cthread.read() # from multi-thread USB camera # Check that it was a valid frame, otherwise try again if frame == None): continue

March 24, 2017 at 8:28 am

Hello Adrian,

If I still get the NoneType errors when running that downloadable code, what does that mean?

I’ve run it in terminal with and without the full address of the image, as well as adding in the, h, w and d but am still getting it.

March 25, 2017 at 9:24 am

If you are still getting NoneType errors after validating that the paths to your images are correct then your version of OpenCV was likely compiled without support to load the image file type.

July 6, 2017 at 1:00 am

Hello Sir, I am getting an open cv error that module object has no attribute cv2.imread ,please solve out this.

im = cv2.imread(“photo_2.jpg”) AttributeError: ‘module’ object has no attribute ‘imread’

July 7, 2017 at 10:01 am

How did you install OpenCV? And which operating system are you using?

April 16, 2018 at 5:06 am

can i use raspberry pi camera in place of webcam

April 16, 2018 at 2:17 pm

Yes, absolutely. Refer to this blog post .

April 30, 2018 at 12:25 pm

hello adrian

I am trying to use your VideoStream code but it gives me an error in the line “freme = inutils.resize (frame, width = 400)” being the famaso error “AttributeError: ‘Nometype? Object has no attribute’ shape ‘”

I have imutils installed and opencv could help me

Thanks in advance for your attention

April 30, 2018 at 1:04 pm

Hi Michell — double check the image path from when you loaded the image. Printing frame to the terminal and see if you have a valid NumPy array.

April 30, 2018 at 1:47 pm

The path of the image? but should not see the video made by the camera?

Thank you for your availability.

May 2, 2018 at 6:21 am

but I’m not loading image from a path but rather doing stremvideo … how can I solve?

Thanks for the availability.

May 3, 2018 at 9:34 am

What video stream are you using? A USB camera? Built-in webcam? A Raspberry Pi camera module?

May 8, 2018 at 7:04 am

I’m using the Raspberry Pi camera module…

May 9, 2018 at 9:45 am

Have you validated that the “raspistill” and “raspivid” commands are properly working? What else have you done to validate that you can access your Raspberry Pi camera module?

May 9, 2018 at 11:44 am

I am also having the same issues. I’m running 4.0.0-pre and using the built in camera module. I was able to test videostream and confirmed “raspistill” and “raspivid” commands are properly working. Any ideas?

May 14, 2018 at 12:25 pm

How are you accessing the Raspberry Pi camera via Python code? Are you using the “picamera” Python module? Or are you using OpenCV’s “cv2.VideoCapture”?

August 14, 2018 at 3:01 am

Hi Adrian, Will you please help me regarding how to zoom in and zoom out an image. I am building my desktop map application for navigating the object from source to destination as well as detecting the object on the map.

August 15, 2018 at 8:35 am

OpenCV really isn’t meant to build GUI applications that zoom in and out. You may want to take a look at other dedicated GUI libraries such as Kivy, TKinter, and Qt.

May 9, 2018 at 1:54 pm

For all those using the Raspberry Pi and using the built in camera and also receiving an AttributeError: ‘NoneType’ object has no attribute ‘shape’ error:

1 make sure the camera is enabled 2 change: VideoStream(src=0).start() To: VideoStream(src=0, usePiCamera=True).start()

The VideoStream function disables the built in camera by default

May 30, 2018 at 11:19 pm

Hello Adrian! I’m so thank you for your perfect blogs! However, I had a same problem just like abvoe suggestions.

================================ [INFO] loading model… [INFO] starting video stream…

… …

(h, w) = image.shape[:2] AttributeError: ‘NoneType’ object has no attribute ‘shape’ ================================

After read about your blogs including this blog, I found a spot with no values.

line 35. vs = VideoStream(src=0).start()

So, I tried to add the only one code following line.

$ sudo modprobe bcm285-v4l2

After insert this line, I can compile the your python code like raspberry pi object detection, real time object detection or etc. This is my solution to this problem. I wish this solution can help your blog or else.

ps. I want to say sorry about poor English. ps2. I successfully finished the school project with your blogs! Thank you again!

May 31, 2018 at 4:54 am

Congrats on completing your school project, great job!

Question: Are you trying to use the VideoStream class on a laptop/desktop with a USB camera? Or are you trying to use your Raspberry Pi with a Raspberry Pi camera module? I need to know more about your setup.

May 31, 2018 at 9:36 pm

I’m sorry to reply late. My project is only focused on the Raspberry Pi with a Raspberry Pi camera module.

June 5, 2018 at 8:31 am

Got it, thank you for sharing. For any other readers who are interested — you can either install the drivers as Lee suggested or you can use the VideoStream class instead with usePiCamera=True . I personally prefer the latter.

October 2, 2018 at 2:02 pm

gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY) AttributeError: module ‘cv2.cv2’ has no attribute ‘cvt’. please help me. Thanks in advance…

October 8, 2018 at 10:33 am

It sounds like you may have a problem with your OpenCV install. Try following one of my OpenCV install guides to help you get OpenCV installed properly.

August 5, 2019 at 12:15 am

My 10 cents. I could not open my file with OpenCV even though the path was absolutely correct.As it turned out, I had saved (cv2.imwrite) this file without image.astype(“uint8”).

August 7, 2019 at 12:27 pm

Thanks for sharing!

February 22, 2020 at 1:04 pm

There is also another problem which is not mentioned here. That is if the file path to image file contains non-ASCII characters the cv2.imread method does not work and gets Nonetype error. I believe you should include this too.

February 27, 2020 at 9:21 am

Great point, thanks for mentioning it!

[…] from disk, likely due to an issue with the image encoding (a phenomenon you can read more about here), so we skip the […]

Comment section

Hey, Adrian Rosebrock here, author and creator of PyImageSearch. While I love hearing from readers, a couple years ago I made the tough decision to no longer offer 1:1 help over blog post comments.

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【Python】TypeError: ‘NoneType’のエラー原因と対処法まとめ（初心者向け・実例でわかりやすく解説）

再帰関数などを使って処理を記述している場合に、次のようなエラーが発生することがあります。

なお、この記事の内容は、上記以外でも「NoneTpye」を含むエラー全般の発生原因と対処法にもなっています。

エラーが発生する状況例

対処法（returnの設置）, returnの設置場所の注意点.

最初に結論を述べると、主な原因は次の２つです。

①戻り値(return)のない関数の実行結果は「値None, タイプNoneType」になる。

②関数を変数に代入する場合は、その関数にreturnがあること。 　└ printではだめ。（実行結果ではなく、実行途中のいち処理のため） 　└ returnは関数の最終出力となっていること。 　└ 関数内のどこかにreturnが1個あればいいというわけではない。

以下で実例を踏まえて原因と対処法について解説しています。

例えば、次のように多次元配列からintを抜き出そうとしたときに、’NoneType’ object is not iterableのエラーが発生します。

‘NoneType’のオブジェクトをいじろうとしていることが原因です。

▼もう少し細かく 「res = number(brr)」で変数に関数number()代入しているが、この関数自体に戻り値(return)がないため、変数にはNoneが格納され、タイプがNoneTypeとなっている。

「result += res」このNoneTypeの変数resと、list型の変数resultを結合しようとしたため、

resはイテラブルじゃないから結合できないと言われている。

関数にデフォルト引数が渡されなかった場合に発生するエラー。値はNoneのみとのこと。

(python公式)Noneとは 型 NoneType の唯一の値です。 None は、関数にデフォルト引数が渡されなかったときなどに、値の非存在を表すのに頻繁に用いられます。 None への代入は不正で、SyntaxError を送出します。

▼簡単にするとこんな感じ 関数の実行結果が空とき、その結果自体がNoneTypeになる。

なので、実行結果が空の関数を変数に代入するとNoneTypeになる。

printの場合もNoneTypeになる

「こんにちは」が出力されているが、関数の実行過程で表示されたもので、関数自体と置き換わるものではない。

NoneTypeとしないために、returnで関数に実態をもたせる。 　└ 戻り値(return)は関数を実行した結果を関数自身と置き換える。

xが文字列「こんにちは」に置き換わっている。

関数の中にreturnがあればいいというわけではありません。実行した最終結果としてreturnを経由する必要があります。

▼returnが記述されているがNoneTypeになる例

1 < 2　のため、関数の出力結果は空になっている。この原因は、returnの処理を経由しないためです。

▼実行結果がreturnを経由する場合はOK

▼関数自体はのタイプはfunction

▼関数自体を変数に代入する場合はカッコ不要, ▼変数（関数を代入）の実行例.

hello()=x()となっている。

冒頭に記述したエラーコードを修正すると以下のようになります。

ポイントは、 変数に代入する値が関数にならないよう、returnを適切に設置する。

以上で無事に処理が動きます。

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Cracking the Shell of Mystery

TypeError: Type object does not support item assignment: How to fix it?

TypeError: Type object does not support item assignment

Have you ever tried to assign a value to a property of a type object and received a TypeError? If so, you’re not alone. This error is a common one, and it can be frustrating to figure out what went wrong.

In this article, we’ll take a look at what a type object is, why you can’t assign values to its properties, and how to avoid this error. We’ll also provide some examples of how to work with type objects correctly.

So, if you’re ready to learn more about TypeErrors and type objects, read on!

What is a type object?

A type object is a special kind of object that represents a data type. For example, the `int` type object represents the integer data type, and the `str` type object represents the string data type.

Type objects are created when you use the `type()` function. For example, the following code creates a type object for the integer data type:

python int_type = type(1)

Type objects have a number of properties that you can use to get information about them. For example, the `__name__` property returns the name of the type, and the `__bases__` property returns a list of the type’s base classes.

Why can’t you assign values to type objects?

Type objects are immutable, which means that their values cannot be changed. This is because type objects are used to represent the abstract concept of a data type, and their values are not meant to be changed.

If you try to assign a value to a property of a type object, you’ll receive a TypeError. For example, the following code will raise a TypeError:

python int_type.name = “New name”

How to avoid TypeErrors

To avoid TypeErrors, you should never try to assign values to properties of type objects. If you need to change the value of a property, you should create a new object with the desired value.

For example, the following code correctly changes the value of the `name` property of an integer object:

python new_int = int(1) new_int.name = “New name”

TypeErrors can be frustrating, but they can usually be avoided by understanding what type objects are and how they work. By following the tips in this article, you can avoid these errors and write more robust code.

| Header 1 | Header 2 | Header 3 | |—|—|—| | TypeError: type object does not support item assignment | Definition | Cause | | An error that occurs when you try to assign a value to an element of a type object that does not support item assignment. | The type object is immutable, which means that its values cannot be changed. | Trying to assign a value to an element of a type object will result in a TypeError. |

A TypeError is a type of error that occurs when an operation or function is applied to an object of an inappropriate type. For example, trying to assign a value to an attribute of a type object will result in a TypeError.

TypeErrors can be difficult to debug, because they can occur in a variety of situations. However, by understanding what causes a TypeError, you can be better equipped to avoid them.

What causes a TypeError?

There are a few different things that can cause a TypeError:

• Using an incompatible data type: One of the most common causes of a TypeError is using an incompatible data type. For example, trying to add a string to a number will result in a TypeError.
• Using an invalid operator: Another common cause of a TypeError is using an invalid operator. For example, trying to divide a number by zero will result in a TypeError.
• Calling a method on an object that doesn’t support it: Finally, trying to call a method on an object that doesn’t support it can also result in a TypeError. For example, trying to call the `.sort()` method on a string will result in a TypeError.

There are a few things you can do to avoid TypeErrors:

• Be careful about the data types you use: Make sure that you are using the correct data types for your operations. For example, if you are adding two numbers, make sure that both numbers are numbers.
• Use the correct operators: Make sure that you are using the correct operators for your operations. For example, if you are dividing two numbers, use the `/` operator.
• Read the documentation: If you are not sure whether a method is supported by an object, read the documentation to find out.

By following these tips, you can help to avoid TypeErrors in your code.

TypeErrors can be a frustrating experience, but they can also be a learning opportunity. By understanding what causes a TypeError, you can be better equipped to avoid them. And by following the tips in this article, you can help to reduce the number of TypeErrors in your code.

Additional resources

• [Python TypeError documentation](https://docs.python.org/3/library/exceptions.htmlTypeError)
• [Stack Overflow: TypeError questions](https://stackoverflow.com/questions/tagged/typeerror)
• [Real Python: How to avoid TypeErrors in Python](https://realpython.com/python-typeerror/)

3. How to fix a TypeError?

To fix a TypeError, you need to identify the cause of the error and then take steps to correct it. Some common fixes include:

Using the correct data type

Using the correct operator

Calling the correct method on the object

Let’s take a look at some examples of how to fix each of these types of errors.

One of the most common causes of TypeErrors is using the wrong data type. For example, if you try to add a string to an integer, you will get a TypeError because strings and integers are different data types. To fix this error, you need to convert the string to an integer or the integer to a string.

x = ‘123’ y = 456

This will raise a TypeError because you cannot add a string to an integer z = x + y

To fix this error, you can convert the string to an integer z = int(x) + y

Another common cause of TypeErrors is using the wrong operator. For example, if you try to divide an integer by a string, you will get a TypeError because you cannot divide an integer by a string. To fix this error, you need to use the correct operator.

x = 123 y = ‘456’

This will raise a TypeError because you cannot divide an integer by a string z = x / y

To fix this error, you can use the `str()` function to convert the string to an integer z = x / int(y)

Finally, another common cause of TypeErrors is calling the wrong method on an object. For example, if you try to call the `len()` method on a string, you will get a TypeError because the `len()` method is not defined for strings. To fix this error, you need to call the correct method on the object.

x = ‘hello’

This will raise a TypeError because the `len()` method is not defined for strings y = len(x)

To fix this error, you can use the `str()` function to convert the string to an integer y = len(str(x))

By following these tips, you can help to avoid TypeErrors in your Python code.

4. Examples of TypeErrors

Here are some examples of TypeErrors:

x = ‘hello’ x[0] = ‘a’

This will result in a TypeError because strings are immutable and cannot be changed.

print(int(‘123’))

This will also result in a TypeError because the string ‘123’ cannot be converted to an integer.

class MyClass: def __init__(self, name): self.name = name

my_class = MyClass(‘John’) my_class.name = ‘Jane’

This will also result in a TypeError because the method `name` is not defined on the `MyClass` object.

TypeErrors are a common problem in Python, but they can be easily avoided by following the tips in this article. By using the correct data types, operators, and methods, you can help to ensure that your Python code is free of errors.

Q: What does the error “TypeError: type object does not support item assignment” mean?

A: This error occurs when you try to assign a value to a property of a type object. For example, the following code will raise an error:

>>> type = type(‘MyType’, (object,), {}) >>> type.name = ‘MyType’ Traceback (most recent call last): File “ “, line 1, in TypeError: type object does not support item assignment

The reason for this error is that type objects are immutable, which means that their properties cannot be changed after they are created. If you need to change the value of a property of a type object, you can create a new type object with the desired value.

Q: How can I fix the error “TypeError: type object does not support item assignment”?

A: There are two ways to fix this error. The first way is to create a new type object with the desired value. For example, the following code will fix the error in the example above:

>>> type = type(‘MyType’, (object,), {‘name’: ‘MyType’}) >>> type.name ‘MyType’

The second way to fix this error is to use a dictionary to store the properties of the type object. For example, the following code will also fix the error in the example above:

>>> type = type(‘MyType’, (object,), {}) >>> type.__dict__[‘name’] = ‘MyType’ >>> type.name ‘MyType’

Q: What are some common causes of the error “TypeError: type object does not support item assignment”?

A: There are a few common causes of this error. The first is trying to assign a value to a property of a type object that does not exist. For example, the following code will raise an error:

>>> type = type(‘MyType’, (object,), {}) >>> type.foo = ‘bar’ Traceback (most recent call last): File “ “, line 1, in AttributeError: type object has no attribute ‘foo’

The second is trying to assign a value to a property of a type object that is read-only. For example, the following code will also raise an error:

>>> type = type(‘MyType’, (object,), {}) >>> type.name = ‘MyType’ Traceback (most recent call last): File “ “, line 1, in TypeError: can’t set attribute ‘name’ of type object

The third is trying to assign a value to a property of a type object that is not a valid type. For example, the following code will also raise an error:

>>> type = type(‘MyType’, (object,), {}) >>> type.name = 123 Traceback (most recent call last): File “ “, line 1, in TypeError: can’t assign int to str object

Q: How can I avoid the error “TypeError: type object does not support item assignment”?

A: There are a few things you can do to avoid this error. First, make sure that you are trying to assign a value to a property of a type object that exists. Second, make sure that you are not trying to assign a value to a property of a type object that is read-only. Third, make sure that you are not trying to assign a value to a property of a type object that is not a valid type.

Here are some specific examples of how to avoid this error:

• Instead of trying to assign a value to the `name` property of a type object, you can create a new type object with the desired value. For example:

>>> type = type(‘MyType’, (object,), {‘name’: ‘MyType’})

• Instead of trying to assign a value to the `name` property of a type object, you can use a dictionary to store the properties of the type object. For example:

>>> type = type(‘MyType’, (object,), {}) >>> type.__dict__[‘name’] = ‘MyType’

• Instead of trying to assign a value to the `name` property of a type object, you can use a getter and setter method to access the property. For example:

In this blog post, we discussed the TypeError: type object does not support item assignment error. We first explained what the error is and then provided several ways to fix it. We also discussed some common causes of the error and how to avoid them.

We hope that this blog post has been helpful and that you now have a better understanding of the TypeError: type object does not support item assignment error. If you have any other questions or comments, please feel free to leave them below.

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TypeError: 'tuple' object does not support item assignment

Last updated: Apr 8, 2024 Reading time · 4 min

# TypeError: 'tuple' object does not support item assignment

The Python "TypeError: 'tuple' object does not support item assignment" occurs when we try to change the value of an item in a tuple.

To solve the error, convert the tuple to a list, change the item at the specific index and convert the list back to a tuple.

Here is an example of how the error occurs.

We tried to update an element in a tuple, but tuple objects are immutable which caused the error.

# Convert the tuple to a list to solve the error

We cannot assign a value to an individual item of a tuple.

Instead, we have to convert the tuple to a list.

This is a three-step process:

• Use the list() class to convert the tuple to a list.
• Update the item at the specified index.
• Use the tuple() class to convert the list back to a tuple.

Once we have a list, we can update the item at the specified index and optionally convert the result back to a tuple.

Python indexes are zero-based, so the first item in a tuple has an index of 0 , and the last item has an index of -1 or len(my_tuple) - 1 .

# Constructing a new tuple with the updated element

Alternatively, you can construct a new tuple that contains the updated element at the specified index.

The get_updated_tuple function takes a tuple, an index and a new value and returns a new tuple with the updated value at the specified index.

The original tuple remains unchanged because tuples are immutable.

We updated the tuple element at index 1 , setting it to Z .

If you only have to do this once, you don't have to define a function.

The code sample achieves the same result without using a reusable function.

The values on the left and right-hand sides of the addition (+) operator have to all be tuples.

The syntax for tuple slicing is my_tuple[start:stop:step] .

The start index is inclusive and the stop index is exclusive (up to, but not including).

If the start index is omitted, it is considered to be 0 , if the stop index is omitted, the slice goes to the end of the tuple.

# Using a list instead of a tuple

Alternatively, you can declare a list from the beginning by wrapping the elements in square brackets (not parentheses).

Declaring a list from the beginning is much more efficient if you have to change the values in the collection often.

Tuples are intended to store values that never change.

# How tuples are constructed in Python

In case you declared a tuple by mistake, tuples are constructed in multiple ways:

• Using a pair of parentheses () creates an empty tuple
• Using a trailing comma - a, or (a,)
• Separating items with commas - a, b or (a, b)
• Using the tuple() constructor

# Checking if the value is a tuple

You can also handle the error by checking if the value is a tuple before the assignment.

If the variable stores a tuple, we set it to a list to be able to update the value at the specified index.

The isinstance() function returns True if the passed-in object is an instance or a subclass of the passed-in class.

If you aren't sure what type a variable stores, use the built-in type() class.

The type class returns the type of an object.

# Additional Resources

You can learn more about the related topics by checking out the following tutorials:

• How to convert a Tuple to an Integer in Python
• How to convert a Tuple to JSON in Python
• Find Min and Max values in Tuple or List of Tuples in Python
• Get the Nth element of a Tuple or List of Tuples in Python
• Creating a Tuple or a Set from user Input in Python
• How to Iterate through a List of Tuples in Python
• Write a List of Tuples to a File in Python
• AttributeError: 'tuple' object has no attribute X in Python
• TypeError: 'tuple' object is not callable in Python [Fixed]

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TypeError: 'NoneType' object does not support item assignment #5780

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TypeError: 'type' object does not support item assignment

this is my code and when I run it, python returns TypeError: 'type' object does not support item assignment. What am I doing wrong?

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TypeError: 'NoneType' object does not support item assignment

I am trying to do some mathematical calculation according to the values at particular index of a NumPy array with the following code

But I am getting the following error

Would you please help me in solving this? Thanks

fill return nothing.

Replace following line:

• now it is showing the following error -- ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.all() –  R S John Commented Oct 26, 2013 at 9:54
• @RSJohn, Replace ind = np.where(X >= 4.0 and X < 9.0) with ind = np.where((X >= 4.0) & (X < 9.0)) –  falsetru Commented Oct 26, 2013 at 10:03

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[Solved] TypeError: ‘str’ Object Does Not Support Item Assignment

In this article, we will be discussing the TypeError:’str’ Object Does Not Support Item Assignment exception . We will also be going through solutions to this problem with example programs.

Why is This Error Raised?

When you attempt to change a character within a string using the assignment operator, you will receive the Python error TypeError: ‘str’ object does not support item assignment.

As we know, strings are immutable. If you attempt to change the content of a string, you will receive the error TypeError: ‘str’ object does not support item assignment .

There are four other similar variations based on immutable data types :

• TypeError: 'tuple' object does not support item assignment
• TypeError: 'int' object does not support item assignment
• TypeError: 'float' object does not support item assignment
• TypeError: 'bool' object does not support item assignment

Replacing String Characters using Assignment Operators

Replicate these errors yourself online to get a better idea here .

In this code, we will attempt to replace characters in a string.

Strings are an immutable data type. However, we can change the memory to a different set of characters like so:

TypeError: ‘str’ Object Does Not Support Item Assignment in JSON

Let’s review the following code, which retrieves data from a JSON file.

In line 5, we are assigning data['sample'] to a string instead of an actual dictionary. This causes the interpreter to believe we are reassigning the value for an immutable string type.

TypeError: ‘str’ Object Does Not Support Item Assignment in PySpark

The following program reads files from a folder in a loop and creates data frames.

This occurs when a PySpark function is overwritten with a string. You can try directly importing the functions like so:

TypeError: ‘str’ Object Does Not Support Item Assignment in PyMongo

The following program writes decoded messages in a MongoDB collection. The decoded message is in a Python Dictionary.

At the 10th visible line, the variable x is converted as a string.

It’s better to use:

Please note that msg are a dictionary and NOT an object of context.

TypeError: ‘str’ Object Does Not Support Item Assignment in Random Shuffle

The below implementation takes an input main and the value is shuffled. The shuffled value is placed into Second .

random.shuffle is being called on a string, which is not supported. Convert the string type into a list and back to a string as an output in Second

TypeError: ‘str’ Object Does Not Support Item Assignment in Pandas Data Frame

The following program attempts to add a new column into the data frame

The iteration statement for dataset in df: loops through all the column names of “sample.csv”. To add an extra column, remove the iteration and simply pass dataset['Column'] = 1 .

These are the causes for TypeErrors : – Incompatible operations between 2 operands: – Passing a non-callable identifier – Incorrect list index type – Iterating a non-iterable identifier.

The data types that support item assignment are: – Lists – Dictionaries – and Sets These data types are mutable and support item assignment

As we know, TypeErrors occur due to unsupported operations between operands. To avoid facing such errors, we must: – Learn Proper Python syntax for all Data Types. – Establish the mutable and immutable Data Types. – Figure how list indexing works and other data types that support indexing. – Explore how function calls work in Python and various ways to call a function. – Establish the difference between an iterable and non-iterable identifier. – Learn the properties of Python Data Types.

We have looked at various error cases in TypeError:’str’ Object Does Not Support Item Assignment. Solutions for these cases have been provided. We have also mentioned similar variations of this exception.

Trending Python Articles

How to Solve Python TypeError: ‘int’ object does not support item assignment

by Suf | Programming , Python , Tips

In Python, integers are single values. You cannot access elements in integers like you can with container objects. If you try to change an integer in-place using the indexing operator [], you will raise the TypeError: ‘int’ object does not support item assignment.

This error can occur when assigning an integer to a variable with the same name as a container object like a list or dictionary.

To solve this error, check the type of the object before the item assignment to make sure it is not an integer.

This tutorial will go through how to solve this error and solve it with the help of code examples.

Table of contents

Typeerror: ‘int’ object does not support item assignment.

Let’s break up the error message to understand what the error means. TypeError occurs whenever you attempt to use an illegal operation for a specific data type.

The part 'int' object tells us that the error concerns an illegal operation for integers.

The part does not support item assignment tells us that item assignment is the illegal operation we are attempting.

Integers are single values and do not contain elements. You must use indexable container objects like lists to perform item assignments.

This error is similar to the TypeError: ‘int’ object is not subscriptable .

Let’s look at an example where we define a function that takes a string holding a phrase, splits the string into words and then stores the counts of each word in a dictionary. The code is as follows:

We will then use the input() method to take a string from the user as follows:

Let’s run the code to see what happens:

The error occurs because we set word_dict to an integer in the try code block with word_dict = value + 1 when we encounter the second occurrence of the word really . Then when the for loop moves to the next word fun which does not exist in the dictionary, we execute the except code block. But word_dict[word] = 1 expects a dictionary called word_dict , not an integer. We cannot perform item assignment on an integer.

We need to ensure that the word_dict variable remains a dictionary throughout the program lifecycle to solve this error. We need to increment the value of the dictionary by one if the word already exists in the dictionary. We can access the value of a dictionary using the subscript operator. Let’s look at the revised code:

The code runs successfully and counts the occurrences of all words in the string.

Congratulations on reading to the end of this tutorial. The TypeError: ‘int’ object does not support item assignment occurs when you try to change the elements of an integer using indexing. Integers are single values and are not indexable.

You may encounter this error when assigning an integer to a variable with the same name as a container object like a list or dictionary.

It is good practice to check the type of objects created when debugging your program.

If you want to perform item assignments, you must use a list or a dictionary.

For further reading on TypeErrors, go to the articles:

• How to Solve Python TypeError: ‘str’ object does not support item assignment
• How to Solve Python TypeError: ‘tuple’ object does not support item assignment

To learn more about Python for data science and machine learning, go to the  online courses page on Python  for the most comprehensive courses available.

Have fun and happy researching!

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