How to Fix the Missing Required Positional Argument Error in Your Python Code

Learn how to resolve the `missing 1 required positional argument` error in your Python program and understand how to effectively use function arguments and exception handling.
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How to Fix the Missing Required Positional Argument Error in Your Python Code

As you embark on your journey of learning Python, you might come across various errors that can leave you scratching your head. One common error is the "missing 1 required positional argument." This error typically arises when you define a function that requires an argument, but you don't actually pass one when calling the function. In this guide, we'll dive deep into a specific example to identify the problem and outline the solution step by step.

The Problem: Missing Required Positional Argument

You have written a Python program designed to print out a relationship message based on a specific key passed as an argument. The intended output is as follows:

If the key is "Lisa", it should print: "John, I am your sister".

If the key is "Smith", it should print: "No, I am your father."

But upon running your code, you encounter a missing 1 required positional argument error. Why is that? Let's break down your code to understand this issue.

Your Original Code

Here is the code you provided:

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

In this snippet, there are a couple of issues to address:

You did not import the sys module.

You did not specify an argument when invoking the Relation function.

The Solution: Fixing Your Code

Step 1: Importing the Required Module

The first step is to import the sys module, which allows you to access command-line arguments. Without this, your program will not work as expected.

Simply add the following line at the beginning of your code:

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

Step 2: Passing Arguments Correctly

The second issue is that you're calling the Relation() function without an argument. Since your function requires an argument (name), you need to ensure you're passing it during the function call. Here’s a revised version of your code:

Revised Code

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

Explanation of Changes

Function Argument: We are now passing name from the command-line arguments when calling the Relation function.

Error Handling: Exception handling has been added to manage scenarios where a key does not exist in the relations dictionary or if no input is provided.

Conclusion

By following these steps, you should be able to resolve the missing 1 required positional argument error and ensure your program runs smoothly. Every coding journey is filled with learning moments—by understanding these errors, you become a stronger Python programmer. Happy coding!