writing elements in matlab listbox - matlab

Question

I am trying to write a list in a listbox.
code:
function listbox1_Callback(hObject, eventdata, handles)
% hObject handle to listbox1 (see GCBO)
% eventdata reserved - to be defined in a future version of MATLAB
% handles structure with handles and user data (see GUIDATA)
% Hints: contents = cellstr(get(hObject,'String')) returns listbox1 contents as cell array
% contents{get(hObject,'Value')} returns selected item from listbox1
error = getappdata(0, 'error_norm');
rows = size(error,1);
for i = 1:rows
set(handles.listbox1,'string',strcat('filt_',num2str(i)));
for j = 1:length(error)
set(handles.listbox1,'string',strcat('sig_',num2str(i),'_',num2str(j)));
for k = 1:length(error{j}.main)
set(handles.listbox1,'string',strcat('seg_',num2str(i),'_',num2str(j),'_',num2str(k)));
end
end
end
Where error is a array of structure, this array contains filters, singals in these filters, segments of these signals. based on the number of all these components, i want to write the list. I want to write something like this in the listbox:
filt_1
sig_1_1
seg_1_1_1
seg_1_1_2
sig_1_2
seg_1_2_1
seg_1_2_2
But apparently, 'set' function overwrites the elements, so all i am getting is 1 element and the last element.
Any suggestion to how to overcome this problem will be appreciated.

Answer 1

Yes, since set always overwrites the string, it is better to firstl build the string and then pass it to set.
Example
% Sample data
rows=4;
error=cell(1,5);
for i=1:length(error)
error{i}.main=rand(1,4);
end
% Build string
str={};
for i=1:rows
str{end+1}=sprintf('filt_%i',i);
for j=1:length(error)
str{end+1}=sprintf('sig_%i_%i',i,j);
for k=1:length(error{j}.main)
str{end+1}=sprintf('seg_%i_%i_%i',i,j,k);
end
end
end
% Set data
set(handle.listbox1,'String', str);
Depending on the size of the final string it might be a good idea to preallocate str for performance.