You can obtain a cell array of the names of variables in the base workspace with the command evalin('base', 'who'). You can then use those strings in evalin('base', str). For example:
% Add some variables to the base workspace yourself
function access_base_vars
f = figure('defaultuicontrolunits', 'normalized');
base_vars = evalin('base', 'who');
gui.menu = uicontrol('style', 'popupmenu', 'string', base_vars, 'callback', @update, 'position', [0.05 0.5 0.2 0.1]);
gui.var_class = uicontrol('style', 'text', 'string', 'Variable Class: ', 'position', [0.3 0.5 0.5 0.1]);
guidata(f, gui);
function update(obj, ~)
str = obj.String{obj.Value};
gui.var_class.String = 'Variable Class: ' + string(class(evalin('base', str)));
end
end
In an actual scenario, you will want to ensure you recalculate evalin('base', 'who') every time before using the strings as the user could have altered the workspace.
