how to plot from input (function)

This is my code so far

function gui01
  
  figure('MenuBar','none','Name','test','NumberTitle','off','Position',[200,200,800,500]);
  
  Text1 = uicontrol('Style','Text','String','Enter a function to draw','Position',[590,300,120,20],...
    'HorizontalAlignment','left');
   GUI.h1 = uicontrol('style','Edit','string','','Units','normalized','Position',[0.6 0.5 0.38 0.08],...
                       'backgroundcolor','w',...
                       'Tag','EditField');
   Draw = uicontrol('Style','PushButton','String','Draw','Position',[620,200,60,20],...
    'CallBack',{@func_compute,GUI.h1,gca});
       set( gca, 'DataAspectRatioMode', 'auto' )
    set(gca,'Position',[0.04, 0.15, 0.5 0.74]); 
    set(gca, 'XLim',[-2,5]);
    set(gca, 'YLim',[-2,5]);
    
    x = linspace(0,2*pi,150);

    function func_compute(~,~,InHandle,OutHandle)
    y = get(InHandle,'String');
    n = str2double(y);
   OutHandle = plot([x,n]);

what I want is to write a function like 3.*x in the text box then it will assigne the function to the varible y and finally it will plot x and y on the axes displaied after pressing draw how can I do it ?

Answer 1

[Geoff Hayes]

@Anwar Alm - you could use str2func to convert the function string to a function handle and then evaluate in your code. In this case, the callback would be changd to

function func_compute(~,~,hEditField,hAxes)
    y = str2func(['@(x)' get(hEditField,'String')]);
    n = str2double(y);
    plot(x,y(x));
end

Note how the @(x) is prepended to the string that we obtain from the edit field (see anonymous functions for details).