how to list variable name and values in the WS into a dropdown menu

Dear all,

I would like to have a dropdown menu that allows me to find and select the variables that I have in my workspace. So that I can use the associated data for other operation.

For example in my workspace I have a variable A that is an array. I would like that in the dropdown menu I see A and when I select it I can use its values (the array)

So far I was able to list in the dropdown meny the variable name but those are just string and do not have the values.

How can I do?

With this code I found in the forum I can make the first part. But then the dropbown menu shows me the names of the varible only. I do not know how to associate to them te values and therefore in the last part in the "assignin" I just have a new variable called app.dataname = value but value is just the name of the variable from the dropdown and its value.

Please any help?

Thank you

Max

function update_menu(app, ~, ~)
    vars = evalin('base', 'whos');
    cell_array = cell(size(vars));
    for i=1:length(vars)
        cell_array{i} = vars(i).name;
    end
    app.PLUTODropDown.Items = cell_array;
end

function results = UIFigureCloseRequest(app, event)
    % Close request function: UIFigure
    stop(app.menu_timer);
    delete(app.menu_timer);
    delete(app)
end

function SavetoWorkspaceButtonPushed(app, event)
    value = app.PLUTODropDown.Value;
    app.dataname;
    assignin('base',app.dataname,value)  % app.dataname e' una stringa gia' quindi non devo mettere gli apici
end

Answer 1

[Oguz Kaan Hancioglu]

You can read any value from workspace using evalin command.

appArray = evalin('base','baseArray')

Unfortunately, in the app designer mosts of the menu are cell. After you read your array you need to create cell array in order to use in dropdown value. You can compare cell values or convert to double in order to use in your app.

[massimo Petrarca]

Thank you.

by using this suggestion " evalin('base','baseArray')"

now it works.

so now it is :

function update_menu(app, ~, ~)

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

cell_array = cell(size(vars));

for i=1:length(vars)

cell_array{i} = vars(i).name;

end

app.PLUTODropDown.Items = cell_array;

end

function results = UIFigureCloseRequest(app, event)

% Close request function: UIFigure

stop(app.menu_timer);

delete(app.menu_timer);

delete(app)

end

function SavetoWorkspaceButtonPushed(app, event)

value = app.PLUTODropDown.Value;

app.dataname;

assignin('base',app.dataname,value) % app.dataname e' una stringa gia' quindi non devo mettere gli apici

end

function SavetoWorkspaceButtonPushed(app, event)

%value = app.PLUTODropDown.Value;

dasalvare=evalin('base',app.PLUTODropDown.Value)

app.dataname;

assignin('base',app.dataname,dasalvare)

end

[massimo Petrarca]

Hello,

I was wondering if you can help also understanding how read the name and the values of the variable that the MAtlab app designer uses but that are not shown in the workspace.

What I mean is:

I load a file and obtain two variable from the graphic interface of Matlab.

Now the two variable are not by default shown in the WS.

So I used to save them to the WS and then call them back if needed.

Now is it possible to know and so to list the name of the variable and their values in the dropdown menu without saving them first on the WS?

thank you

Max

[Stephen23]

"the name and the values of the variable that the MAtlab app designer uses but that are not shown in the workspace."

Which workspace do you mean? The workspaces within the app's callback functions are where you should be processing your data, and all of the app's properties and variables are easily available there:

https://www.mathworks.com/help/matlab/creating_guis/share-data-across-callbacks-in-app-designer.html

Making everything magically appear in the base workspace just makes everything more complex.

"Now is it possible to know and so to list the name of the variable and their values in the dropdown menu without saving them first on the WS?"

Yes: simply process the data inside the app, just like GUIs are designed for.

[massimo Petrarca]

Hi,

what I need is a dropdown menu that shows me and allows me to select the different variables I am using and creating.

So far, I was able to have a dropdown menu capable to read and select the variables in the base WS .

For example I open a file and create two array within app. designer. But I am not able to see them in the dropdown menu and select their values to make further operation. So I save them in the base WS and then I can read and select them from the dropdown menu thanks to the script I shown on top.

how can I have my dropdown menu showing the vector I produce and allowing me to select them for further operation?

thank you again

Max

[Oguz Kaan Hancioglu]

You can use struct array to keep you data in your app designer. For example;

S(1).number = 1;
S(1).name = 'First Array';
S(1).data = [......];
S(2).number = 2;
S(2).name = 'First Array';
S(2).data = [......]

When you create new array, you just need to add new element to the struct. After that, you can show this struct (maybe jsut struct's name) in the dropdown menu.

You can use or create another sturcture just like this.

Best

[massimo Petrarca]

Hi,

thanks this is useful.

The problem is that in this case I need every time I create a new array to add an item to the strycture array by writing the code. I do not know if this can be done dynamically.

In the code I posted ubove, every time there is a e new array for example it is seen and the name is added to the drpdown. In this case the only problem for me is that I am so far able to see only the array in base WS and not those that I created in the app design.

Is this possible ? or may be I am not getting your suggestion to the bottom...

[Oguz Kaan Hancioglu]

Hi,

The problem is that in this case I need every time I create a new array to add an item to the strycture array by writing the code. I do not know if this can be done dynamically.

Yes, you can do it dynamically.

In the code I posted ubove, every time there is a e new array for example it is seen and the name is added to the drpdown. In this case the only problem for me is that I am so far able to see only the array in base WS and not those that I created in the app design.

Each function, gui, simulink have their individual scope. WS is the main scope. App designer is a event based system. Therefore when you implement your code within calbacks of the scope of the array that you created within the callback. In order to access anywhere in the app designer you need to design in public property as @Stephen23 mentioned earlier. In short, you can save or access you array by assigning app.myarray = [...]

Best

[massimo Petrarca]

Dear all,

thank you for your answer.

I apologise but I still do not know how to do it. In my code I used public properties.

Below I post my code so far. With this code I can in the dropdown see and load the wariable in the base WS change their name and save them again in the WS.

But I do not know how to tell the dropdown menu how to show the arays created in the App designer and how to shoe the new arrays that I can created during the app is running.

I am probably missing some basic knowledge.

Is there any example ?

thanks

Max

classdef CaricaVariabili_v1 < matlab.apps.AppBase
    % Properties that correspond to app components
    properties (Access = public)
        UIFigure                matlab.ui.Figure
        PLUTODropDownLabel      matlab.ui.control.Label
        PLUTODropDown           matlab.ui.control.DropDown
        LoadDataButton          matlab.ui.control.Button
        NameDataEditFieldLabel  matlab.ui.control.Label
        NameDataEditField       matlab.ui.control.EditField
        SavetoWorkspaceButton   matlab.ui.control.Button
        FFTButton               matlab.ui.control.Button
        PIPPODropDownLabel      matlab.ui.control.Label
        PIPPODropDown           matlab.ui.control.DropDown
        DIVIONEButton           matlab.ui.control.Button
        DeleteVarButton         matlab.ui.control.Button
    end
    
    properties (Access = public)
        aggiorna=1  %inizializzo il valore a 1
        
        
        Property % Description
        menu_timer % Description
        dataname
        x
        y
        segnale1
        segnale2
        frequenza1
        frequenza2 
        fft_Campo1
        campo1
        campo2
        asse_t1
        risultato
        
    end
    
    methods (Access = public)
        
        function update_menu(app, ~, ~)
            vars = evalin('base', 'whos');
            cell_array = cell(size(vars));
            for i=1:length(vars)
                cell_array{i} = vars(i).name;
            end
            app.PLUTODropDown.Items = cell_array;
            app.PIPPODropDown.Items = cell_array;
        end
        
        function results = UIFigureCloseRequest(app, event)
            % Close request function: UIFigure
            stop(app.menu_timer);
            delete(app.menu_timer);
            delete(app)
            
        end
        
        function results = aggiornaGrafico(app)
            app.dataname
        end
        
        
        function [fft_segnale,asse_t] = FFT(app, segnaleingresso, frequenze)
            
            f=frequenze;
            N=length(f);
            df=(f(end)-f(1))/length(f)  % in GHz
            RangeF=(f(end)-f(1))
            DT=1/RangeF  % in ns
            rangeT=DT*N
            
            %%
            TT1=-rangeT/2:DT:(rangeT/2)-DT; 
            %TT1=0:DT:(rangeT)-DT; 
            TT1=TT1';
            
            asse_t=TT1;    
            fft_segnale = fftshift(fft(fftshift(segnaleingresso)));
            
            
        end
    end
    % Callbacks that handle component events
    methods (Access = private)
        
        % Code that executes after component creation
        function startupFcn(app)
            app.menu_timer = timer('ExecutionMode', 'fixedRate', ...
                'Period', 1, ...
                'TimerFcn', @app.update_menu);
            start(app.menu_timer);
            
        end
        
        % Value changing function: NameDataEditField
        function NameDataEditFieldValueChanging(app, event)
            %changingValue = event.Value;
            app.dataname = event.Value;
            %app.Centrosl1 = event.Value;
            if app.aggiorna
                aggiornaGrafico(app)
            end
        end
        % Button pushed function: SavetoWorkspaceButton
        function SavetoWorkspaceButtonPushed(app, event)
            %value = app.PLUTODropDown.Value;
            dasalvare=evalin('base',app.PLUTODropDown.Value) %leggo i valori della stringa che seleziono con il dropdown menu  e che sono le  WS e li associo alla variabile "dasalvare"
            app.dataname;
            assignin('base',app.dataname,dasalvare) % app.dataname e' una stringa gia' quindi non devo mettere gli apici
            
        end
        
        % Button pushed function: LoadDataButton
        function LoadDataButtonPushed(app, event)
            [filename, pathname] = uigetfile({'*.csv'},'File Selector');
            if ~ischar(filename)
                return;  % User aborted the file selection
            end
            file = fullfile(pathname, filename)
            fid = fopen(file, 'r')
            B=textscan(fid, ' %f %f %f ' , 'Delimiter', ',,' ,'HeaderLines',1)
            C=cell2mat(B);
            app.y=C(:,2); %campo
            app.x=C(:,1);  %frequenze segnale 1
            %app.tempo=zeros(1,length(C(:,3)))';
            %tempo=app.tempo';
            %app.campo1=app.y;
            assignin('base','field1',app.y)
            assignin('base','t1',app.x)
        end
        
        % Value changed function: PLUTODropDown
        function PLUTODropDownValueChanged(app, event)
            value = app.PLUTODropDown.Value;
            
        end
        % Button pushed function: FFTButton
        function FFTButtonPushed(app, event)
            Ydatrasformare=evalin('base',app.PLUTODropDown.Value) 
            Xdatrasformare=evalin('base',app.PLUTODropDown.Value) 
            
            [app.fft_Campo1,app.asse_t1] = FFT(app, Ydatrasformare , Xdatrasformare);   
            assignin('base','ytrasf',app.fft_Campo1)
            assignin('base','xtrasf',app.asse_t1)
            
        end
        
        % Button pushed function: DIVIONEButton
        function DIVIONEButtonPushed(app, event)
            Y=evalin('base',app.PLUTODropDown.Value) 
            X=evalin('base',app.PIPPODropDown.Value) 
            app.risultato=Y./X;
            assignin('base','y_div_x',app.risultato)
            
        end
        
        % Button pushed function: DeleteVarButton
        function DeleteVarButtonPushed(app, event)
            
            evalin('base','clear all')
            
            
        end
    end
    
    % Component initialization
    methods (Access = private)
        
        % Create UIFigure and components
        function createComponents(app)
            
            % Create UIFigure and hide until all components are created
            app.UIFigure = uifigure('Visible', 'off');
            app.UIFigure.Position = [100 100 971 475];
            app.UIFigure.Name = 'MATLAB App';
            
            % Create PLUTODropDownLabel
            app.PLUTODropDownLabel = uilabel(app.UIFigure);
            app.PLUTODropDownLabel.HorizontalAlignment = 'right';
            app.PLUTODropDownLabel.Position = [76 355 45 22];
            app.PLUTODropDownLabel.Text = 'PLUTO';
            % Create PLUTODropDown
            app.PLUTODropDown = uidropdown(app.UIFigure);
            app.PLUTODropDown.ValueChangedFcn = createCallbackFcn(app, @PLUTODropDownValueChanged, true);
            app.PLUTODropDown.Position = [136 355 100 22];
            
            % Create LoadDataButton
            app.LoadDataButton = uibutton(app.UIFigure, 'push');
            app.LoadDataButton.ButtonPushedFcn = createCallbackFcn(app, @LoadDataButtonPushed, true);
            app.LoadDataButton.Position = [49 431 100 22];
            app.LoadDataButton.Text = 'LoadData';
            % Create NameDataEditFieldLabel
            app.NameDataEditFieldLabel = uilabel(app.UIFigure);
            app.NameDataEditFieldLabel.HorizontalAlignment = 'right';
            app.NameDataEditFieldLabel.Position = [202 431 62 22];
            app.NameDataEditFieldLabel.Text = 'NameData';
            % Create NameDataEditField
            app.NameDataEditField = uieditfield(app.UIFigure, 'text');
            app.NameDataEditField.ValueChangingFcn = createCallbackFcn(app, @NameDataEditFieldValueChanging, true);
            app.NameDataEditField.Position = [279 431 100 22];
            
            % Create SavetoWorkspaceButton
            app.SavetoWorkspaceButton = uibutton(app.UIFigure, 'push');
            app.SavetoWorkspaceButton.ButtonPushedFcn = createCallbackFcn(app, @SavetoWorkspaceButtonPushed, true);
            app.SavetoWorkspaceButton.Position = [425 431 113 22];
            app.SavetoWorkspaceButton.Text = 'SavetoWorkspace';
            % Create FFTButton
            app.FFTButton = uibutton(app.UIFigure, 'push');
            app.FFTButton.ButtonPushedFcn = createCallbackFcn(app, @FFTButtonPushed, true);
            app.FFTButton.Position = [136 233 100 22];
            app.FFTButton.Text = 'FFT';
            % Create PIPPODropDownLabel
            app.PIPPODropDownLabel = uilabel(app.UIFigure);
            app.PIPPODropDownLabel.HorizontalAlignment = 'right';
            app.PIPPODropDownLabel.Position = [80 168 41 22];
            app.PIPPODropDownLabel.Text = 'PIPPO';
            % Create PIPPODropDown
            app.PIPPODropDown = uidropdown(app.UIFigure);
            app.PIPPODropDown.Position = [136 168 100 22];
            % Create DIVIONEButton
            app.DIVIONEButton = uibutton(app.UIFigure, 'push');
            app.DIVIONEButton.ButtonPushedFcn = createCallbackFcn(app, @DIVIONEButtonPushed, true);
            app.DIVIONEButton.Position = [59 47 100 22];
            app.DIVIONEButton.Text = 'DIVIONE';
            % Create DeleteVarButton
            app.DeleteVarButton = uibutton(app.UIFigure, 'push');
            app.DeleteVarButton.ButtonPushedFcn = createCallbackFcn(app, @DeleteVarButtonPushed, true);
            app.DeleteVarButton.Position = [655 431 100 22];
            app.DeleteVarButton.Text = 'Delete Var';
            % Show the figure after all components are created
            app.UIFigure.Visible = 'on';
        end
    end
    
    % App creation and deletion
    methods (Access = public)
        
        % Construct app
        function app = CaricaVariabili_v1
            
            % Create UIFigure and components
            createComponents(app)
            
            % Register the app with App Designer
            registerApp(app, app.UIFigure)
            
            % Execute the startup function
            runStartupFcn(app, @startupFcn)
            
            if nargout == 0
                clear app
            end
        end
        
        % Code that executes before app deletion
        function delete(app)
            
            % Delete UIFigure when app is deleted
            delete(app.UIFigure)
        end
    end
end

[Oguz Kaan Hancioglu]

You can do it dynamically.

There is another solution. You can use assignin command to define your arrays in the base workspace. After than you can use them in the dropdown menu.

When you create a new array assign to base workspace.

assignin('base','myArrayName',myArray);

I hope it works.

Best