Accessing and editing workspace values in matlab code

I need to search a variable in workspace and edit its value at some specific index. How do i access, edit that variable and save new value back to workspace. Thanks,

Answer 1

[Friedrich]

You code looks correct so far (little typo in the assignin command, it must be array instead of arraya). But I think this should be faster since you have to copy one value only:

function test(mystruct)
for i=1:1
    assignin('base','tmp',mystruct(i).value)
    cmd_string = [mystruct(i).name,'(',num2str(mystruct(i).rowIndex),',',num2str(mystruct(i).colIndex),')=tmp;clear tmp'];
    evalin('base',cmd_string)
end

end

I tested it with:

    a = [1 2 3 4]
    mystruct.name = 'a'
    mystruct.rowIndex = 1;
    mystruct.colIndex = 1;
    mystruct.value = 14;
    test(mystruct)

[Sadanand]

thank u so much bro..

Answer 2

[Friedrich]

I think what you are looking for is the evalin command. So something like

evalin('base','a=3')

Or if you really have to search you can do:

var = evalin('base','whos;')

[Sadanand]

Thnks for ur response.

I can get workspace variable with evalin command but then i need to modify some value of that variable.

Lets say that workspace variable is array. i want to access that variable in my code and modify its value at specific index.

Please help.

[Friedrich]

You can do it this way:

%base workspace

base_array = 1:10;

%do this in function

array = evalin('base','base_array;')

array(3) = 37;

assignin('base','base_array',array)

But this will copy the full array everytime.

[Friedrich]

Or when single value is needed:

array_at_index = evalin('base','base_array(3);')

array_at_index = array_at_index * 2;

assignin('base','tmp',array_at_index)

evalin('base','base_array(3) = tmp;clear tmp;')

[Sadanand]

Name of the workspace variable is present in some other variable. Lets say workspace variable name is "ABC" and it is present in variable x.

So when i write evalin('base', x) it throws error. I have to give second parameter in single quotes. When i write evalin('base', 'x'), it searches for x instead of ABC. Any solution would be appreciated.

[Friedrich]

Sure evalin('base',x) throws an error since x is not present it the ML workspace. you have to ways here how to proceed and both are stated above:

1.) assignin('base','ABC',x) %will overwrite variable ABC with the values of x

2.)assignin('base','x',x) %copy the variable in the ML Workspace

evalin('base','ABC(some_index) = x; clear x')

[Sadanand]

Sorry to borrow your time again. Here is my actual problem. I have function that takes array of structure. Structure has following fields.

name, rowIndex, columnIndex, value. For each structure in the structure array, i need to get struct.name and search it in workspace and replace value of this workspace variable with struct.value at index struct.rowIndex and struct.colIndex.

Here is what i have written.

function myFuction(mystruct)

for i=1: 2

array = evalin('base', mystruct(i).name);

array(mystruct(i).rowIndex, mystruct(i).colIndex) = mystruct(i).value;

assignin('base', mystruct(i).name, arraya);

clear array;

end

end

Thank You for your help.

Answer 3

[yasser]

am looking for value in some workspaces, can i get name of workspace and index of [row,col]? how to do that?