Assuming that you are using GUIDE to develop your GUI, suppose you have your callback for push button 1, tagged as push1 as
% --- Executes on button press in push1.
function push1_Callback(hObject, eventdata, handles)
% get the path to and name of file to load
[filename,path] = uigetfile('*fs.dat');
if ischar(filename)
% concatenate the filename with the path
fullpathToFile = fullfile(path,filename);
% save the full path to handles
handles.myfile = fullpathToFile;
% write the file name to edit1
set(handles.edit1,'String',filename);
% extract the number between the last underscore and fs
fileId = char(regexp(fullpathToFile,'_[0-9]+fs','match'));
% remove the underscore and fs
fileId = fileId(2:end-2);
% write the file id to edit2
set(handles.edit2,'String',fileId);
% save the user-defined GUI data
guidata(hObject,handles);
end
The above use uigetfile to allow the user to select the fs.dat file to load. The name of the file is saved to the *handles structure for future reference. The set command is used "write" the filename (and later file integer ID) to the edit text widgets. We then use regexp to match in the string for an integer (with one or more digits, hence the +) between and underscore and the 'fs' text. Finally, we save the updated handles structure with guidata.
To go the other direction, in your other callback, you will want to use the get call to grab the integer (that the user has changed) from the edit2 widget, and you can use regexprep to replace the original ID with this one
newFileId = ['_' char(get(handles.edit2,'String')) 'fs'];
handles.myfile = regexprep(handles.myfile,'_[0-9]+fs',newFileId);
guidata(hObject,handles);
Given the above, you should be able to construct your two callbacks to do what you want.
