MATLAB: Appending Matrix

arrayguide

Hello everyone,
I have this code that writes zeros to a matrix based on the length of a listbox and popupmenu options. 1s are written to the matrix based on selections from the popupmenu and listbox:
      function [] = pop_ex()
      % Help goes here.
      S.fh = figure('units','pixels',...
                    'position',[200 400 320 340],...
                    'menubar','none',...
                    'name','slider_ex',...
                    'numbertitle','off',...
                    'resize','off');
      S.pp = uicontrol('style','pop',...
                       'unit','pix',...
                       'position',[20 20 80 40],...
                       'string',{'one','two','three','four'},...
                       'callback',@pp_call); 
      S.ls = uicontrol('style','list',...
                       'unit','pix',...
                       'position',[20 80 80 40],...
                       'min',0,'max',5,...
                       'string',{'lone','ltwo','lthree','lfour','lfive','lsix'});
        guidata(S.fh,S)  
        function [] = pp_call(varargin) 
        % Callback for the popup.
        S = guidata(gcbf);
        A =            zeros(length(get(S.pp,'string')),length(get(S.ls,'string'))); %create matrix A, fill with zeros based on length of popup and list items
        A(get(S.pp,'val'),get(S.ls,'val')) = 1;
      %write 1s for selected items
        A
        %output A
The code works however, I want to append the matrix instead of creating a new one each time.

Best Answer

So it's not really append A, rather it is setting one element of A to 1 one at a time. What you need is to load A from guidata at the beginning of the callback function. save A to guidata at the end of the callback function. The setting of A to all zeros is better to put in the CreateFcn callback.
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