Since you already have a file name called lets say 'data_001.dat' and the folder path from the first file store those in handles if you're using GUIDE. with this you can access these in other functions. you can extract the file numbers like this:
%in initial load pushbutton
[handles.file_1 handles.folderpath] = uigetfile(); %if using GUIDE will save it inside the handles structure.
% file_1 = 'data_001.dat'; %just as an example to test.
pat = '_(\w*).dat';
num = regexp(file_1,pat,'tokens');
set(handles.editbox2,'string',num{:});
so now we have the numbers of the original dat file and the other edit box is populated with this. then since we saved the folderpath inside handles if we go to the editbox callback (which should run when editbox is edited then you can
%in edit box 2 callback or other pushbutton
newfilenum = get(handles.editbox2,'string');
pat = '_(\w*).dat';
handles.file_2 = regexprep(handles.file_1,pat,newfilenum)
load(fullfile(handles.folderpath,handles.file_2));
probably should go with a pushbutton as without some additional codes the editbox callback maybe run if someone clicks in and clicks out without changing anything (it's been a while so i can't remember).
