MATLAB: Construct Timer using evalin

evalintimer

I am working on a gui and I want to make a timer in workspace. I use this command but it occured error:

evalin('base','Timer=timer');

evalin('base',['Timer.Name=' 'Timer01']); It cannot change timer name. Please help me.

Best Answer

Creating the timer in the base workspace may make sense, if you really want the variable Timer to be there, but it is not likely what you want to do. Timer objects are handle objects and you can create the object in one workspace and then get the object with timerfindall from any workspace.

There is no reason that you need to rename the timer object in the base workspace. You can find the object in your current workspace and rename it there.

Even better would be to rename the timer when you create it

evalin('base','Timer=timer(''Name'', ''Timer01'')');

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MATLAB: Use of Evalin

names = evalin('base', 'SensorList.sensorname');
for i = 1:str2num(get(handles.nosensorentry_tag,'string'))
  set(handles.sensname(i), 'String', names(i,1));
end

MATLAB: Evalin Loop Workspace fints

Davin - have you tried stepping through the code to see what is happening? Let's suppose that you have a function called myFunc, and you have the five (fints) tables in the workspace. In the Command Window you type

 myFunc

Now suppose the definition for this function uses your second code example

 function myFunc
 Global = []
 a = who
 for i = 1:length(a)
    Data = evalin('base', [a{i}.Close])
    Global = [Global; Data(:,2)]
 end

The first line of code declares an empty array named Global. This should be renamed so as not to be confused with the built-in MATLAB global "qualifier" for global variables. Perhaps name it given the data that is being used to populate it: allCloseData. The next line calls the who function which, since we are evaluating it from a function, will return only those variables that have been declared in this function. I think that you want to grab the variables in the base workspace. So try

 allBaseVars = evalin('base','who');

Now, you iterate over each one and grab the last (close) column. You mentioned that you are concerned with accessing variables that aren't of type fints - so just add a check on the class type

 for k=1:length(allBaseVars)
    classType = evalin('base',['class(' allBaseVars{k} ')']);
    if strcmpi(classType,'fints')
       % do stuff
    end
 end

I don't have the Financial Toolbox so I'm guessing that the class type of a Financial Time Series object is fints. You can verify this easily enough by just type class(myFintsTable) in the Command Window and seeing what is returned.

Now we can "do stuff" if the object is of type fints. The code will be similar to what you have shown, but the expression (the second input to evalin) must be a string and not the statement hat you have shown

 data = evalin('base',[allBaseVars{k} '.Close']);
 allCloseData = [allCloseData ; data];

So your function now becomes

 function myFunc
 allCloseData = [];
 allBaseVars  = evalin('base','who');
 for k=1:length(allBaseVars)
    classType = evalin('base',['class(' allBaseVars{k} ')']);
    if strcmpi(classType,'fints')
       data = evalin('base',[allBaseVars{k} '.Close']);
       allCloseData = [allCloseData ; data];    
    end
 end

If you want to assign the allCloseData to the base workspace, then just add the following line of code to your function

 assignin('base', 'allCloseData', allCloseData);

Best Answer

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MATLAB: Use of Evalin

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