Скачать или смотреть How to Fix the missing 1 required positional argument: 'self' Error in Python

Learn how to resolve the common Python error `missing 1 required positional argument: 'self'` with clear explanations and practical examples.
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Understanding the "missing 1 required positional argument: 'self'" Error in Python

If you're a Python programmer, there's a good chance you've encountered various error messages. One such common error, especially when working with classes, is the infamous missing 1 required positional argument: 'self'. This can be a source of frustration as it halts your program and raises a red flag about your code. In this guide, we'll explore the meaning behind this error and how to effectively resolve it with clear steps and examples.

What Does the Error Mean?

When you see the TypeError: get_process_by_name() missing 1 required positional argument: 'self', it indicates that Python cannot find the self argument when you call a class method. In Python, self refers to the instance of the class and is a required first parameter for any instance method you define in a class. This error typically arises when:

You forget to create an instance of the class before calling the method.

You attempt to call an instance method directly from the class without instantiating it.

Example of the Error

To illustrate, consider the following code snippet that leads to this error:

[[See Video to Reveal this Text or Code Snippet]]

In this case, get_process_by_name is an instance method of the ReadWriteMemory class, but it's being called directly on the class itself without an instance. This is why Python raises the error regarding the missing self argument.

How to Fix the Error

To resolve this error, you need to create an instance of your class before calling the method. This is how you can do it:

Step 1: Create an Instance of the Class

You need to instantiate the class before calling the method, like this:

[[See Video to Reveal this Text or Code Snippet]]

Step 2: Explanation of the Code

Instantiate the Class:

memory = ReadWriteMemory() creates a new instance of the ReadWriteMemory class, allowing you to access its instance methods.

Calling the Method:

Now that you have an instance (in this case, memory), you can call get_process_by_name correctly, passing the required process_name argument.

Open the Process:

Lastly, you call the open method on the obtained process with process.open().

Conclusion

Fixing the missing 1 required positional argument: 'self' error involves understanding how to use class instances in Python. By ensuring you're calling methods on instances of your classes, you'll prevent this type of error and make your code more robust.

Remember, creating class instances is a fundamental concept in object-oriented programming, and mastering it will save you much time and reduce confusion when debugging your Python code. Happy coding!