How to pick a value inside of a .mat file?

Hey all,

I have .mat file that contains 14k double variables and their values. Also, I have a workspace that contains some of those signals and more. I want to change values of the workspace variables with the ones in the .mat file. So, how can I check if my workspace has a copy of the singal in the .mat file and change its value? And, apply it for all 14k variables respectively?

Thanks.

[Stephen23]

"...apply it for all 14k variables..."

Are those 14k variables unfortunately stored separately in the workspace, or sensibly in an array?

[Hasan Kaan Tuna]

Those 14k variables are stored in a 14kx1 matrix as .mat file which is defined in workspace.

[Dyuman Joshi]

You can use ismember or ismembertol, then use logical indexing to do any operation you want to do.

If you want a specific solution, attach your data or a sample of data if the original data is big enough to attach. Use the paperclip button to attach the data file(s).

[Hasan Kaan Tuna]

Can I use ismember like: ismember(MatFileWith14kVariables, ws) ? In this example ws stands for workspace. If answer is no; let's say my .mat file with 14k variables is named as FKV and, it is defined in workspace. How can I check if a variable defined in FKV is also defined in workspace? Also, how can I change that specific variable's value in workspace with the one in FKV?

[Stephen23]

"Can I use ismember like: ismember(MatFileWith14kVariables, ws) ? In this example ws stands for workspace."

I see nothing in the ISMEMBER documentation to suggest that it supports a "workspace" as an input argument (whatever that means). The ISMEMBER documentation states what input arguments it supports:

https://www.mathworks.com/help/matlab/ref/double.ismember.html#btcnv43-1-A

But given that the word "workspace" has a very specific meaning in MATLAB:

https://www.mathworks.com/help/matlab/matlab_prog/base-and-function-workspaces.html

which contradicts your explanation given here, we can only conclude that either your explanations are inaccurate or you are using standard terms to mean other things. That makes it very hard for us to help you.

Answer 1

[Pratyush]

Hi Hasan,

I understand that you have some variables defined in the workspace and you want to update the variables from thier value stored in a .mat file. You only want to update those variables of your workspace which are present in your .mat file. You can use "load" function to do this. Use the following command.

% make an array of variables in your workspace
varNames = who;

% Load the specific variables from the .mat file
load('your_file.mat', varNames{:});

This would update the variables of your workspace with their value present in the .mat file and leave the variables that are not present in the .mat file unmodified.Refer to the documentation for more detail: Load variables from file into workspace.