How to Solve the Undefined function or variable Error in Matlab When Calling Functions from CMD

Описание: Learn how to properly pass arguments to Matlab functions from CMD, avoiding the `undefined function or variable` error.
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This video is based on the question https://stackoverflow.com/q/62680098/ asked by the user 'Ali Abdari' ( https://stackoverflow.com/u/11736291/ ) and on the answer https://stackoverflow.com/a/62680322/ provided by the user 'Paolo' ( https://stackoverflow.com/u/3390419/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Resolving the Undefined function or variable Error in Matlab from CMD

When working with Matlab, especially when integrating it with command line operations, you might encounter various issues. One common problem arises when calling a function from the command line and passing arguments to it. Specifically, you may face an error stating Undefined function or variable 'hello' even when you intend to pass a simple string. This can be confusing, but fortunately, there's a straightforward solution.

The Problem

Imagine you have a simple Matlab function defined as follows:

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

When you attempt to call this function from the command line (CMD) using the following command:

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

You might expect it to work smoothly. However, instead of the expected result, you encounter an error message that reads:

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

Why Does This Happen?

The error occurs because in Matlab, when you provide a string as an argument in a command line execution, it must be enclosed in single quotes (as opposed to double quotes). Double quotes are interpreted differently, which leads to confusion in function calls.

The Solution

To resolve this issue and correctly pass strings to your function in Matlab, you should modify your command to use single quotes for the string argument. Here’s how you can do this:

Correct Command Usage

Instead of using:

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

You should invoke the function like this:

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

Summary of Steps

Define your Matlab function normally.

Open your command line interface (CMD).

When running your function through CMD, enclose string arguments in single quotes.

Execute the modified command, and you should see the output without errors.

Conclusion

By correctly using single quotes when passing string arguments to functions in Matlab from the command line, you can avoid the frustrating Undefined function or variable error. This small adjustment can save you a lot of time and confusion, ensuring that your functions run as intended.

Feel free to share this helpful solution with anyone who might be facing the same issue!