function assignin overwrites my data

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Teresa Carneiro 2021-7-9

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评论： Matt J 2021-7-9

Hello! I'm trying to save a matrix in the matlab workspace with the function assignin, because that's the only one I know that does this, but the problem is that I don't know if I can manipulate it in order to not overwrite the data I acquire in which loop.

So I'm using this line of code:

assignin('base', varName, captureData);

But the matrix it generates only has the last second of data it captures (each loop is one second) and I need it to save all of the data it gets. I can save it to a txt file, which I'm already doing. But I want to manipulate the generated matrix so I really need the data to be inside of matlab workspace (I'm acquiring data in real time).

Would really appreciate some help, please keep in mind I'm very new to matlab.

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Rik 2021-7-9

Why are you using assignin instead of using functions (or even classes, if you want more persistence)?

Teresa Carneiro 2021-7-9

Okay so I'm actually using this 4 functions https://www.mathworks.com/help/daq/software-analog-triggered-data-capture.html and the main one, softwareAnalogTriggerCapture, calls the function dataCapture. Inside of the dataCapture function there is this line of code that creates this matrix in the matlab workspace. I don't know how to do it in other way.

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Matt J 2021-7-9

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编辑：Matt J 2021-7-9

Do not return a result to the base workspace in each pass through the loop. At the completion of your loop, you should have accumulated a vector containing all the results. You should pass that back to the base workspace.

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Teresa Carneiro 2021-7-9

Okay I just realized that the variable is only saved after I run the code, I needed to be able to change values of the matrix while the code was running. Is there anyway?

Matt J 2021-7-9

在 MATLAB Online 中打开

If you find a way for it to restart the variable when I run the main function again that would be great.

persistent cumulativeData
cumulativeData=[cumulativeData;captureData];
assignin('base', varName, cumulativeData);

Okay I just realized that the variable is only saved after I run the code, I needed to be able to change values of the matrix while the code was running.

Not sure i understand what you wrote here, but with the above, you can insert any changes you wish to cumulativeData before the call to assignin.

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