matlab gui handles for unknown matrix size - matlab

Question

I am writing a GUI now which contains a button that load a matrix:
function Load_Profile_Callback(hObject, eventdata, handles)
% hObject handle to Load_Profile (see GCBO)
% eventdata reserved - to be defined in a future version of MATLAB
% handles structure with handles and user data (see GUIDATA)
[FileName PathName] = uigetfile('*.mat','MATLAB Files');
handles.matrix=importdata([PathName FileName]);
next, i want to define each column of this matrix to be different channel for example:
handles.Ch01Gr01=handles.matrix.Data(:,2);
handles.Ch01Gr02=handles.matrix.Data(:,3);
handles.Ch01Gr03=handles.matrix.Data(:,4);
handles.Ch01Gr04=handles.matrix.Data(:,5);
handles.Ch01Gr05=handles.matrix.Data(:,6);
handles.Ch01Gr06=handles.matrix.Data(:,7);
handles.Ch01Gr07=handles.matrix.Data(:,8);
In case i dont know how many columns there are in this matrix,
is there any option to solve this in for loop (or anyother idea will be good aswell )to run on this matrix dimension?

Answer 1

You can create a cell array for channel:
numch = size(handles.matrix, 2);
for i = 1:numch
handles.Ch01Gr{i} = handles.matrix.Data(:, i);
end

Answer 2

You can check for the number of column before entering the loop and then create dynamic fields to name them according to the loop index (Check here).
Here is a sample GUI in which pressing the button results in loading matrix A (a magic 4x4 matrix...A = magic(4)), which I stored in file 'A.mat'.
function LoadDataGUI
clc
clear
hfigure = figure('Position',[200 200 100 100]);
handles.LoadButton = uicontrol('Style','push','Position',[50 50 50 20],'String','Load','Callback',#(s,e) LoadDataCllbck);
guidata(hfigure,handles);
function LoadDataCllbck
handles = guidata(hfigure);
%// Load matrix. A is actually a magic(4) matrix.
handles.Data = load('A.mat');
%// Check # of columns
NumCol = size(handles.Data.A,2);
for k = 2:NumCol
%// Create dynamic field name
CurrField = sprintf('Ch01Gr%i',k-1);
%// Assign it to the handles structure.
handles.(CurrField) = handles.Data.A(:,k);
end
guidata(hfigure,handles);
end
end
Here, CurrField look like this at every iteration:
CurrField =
Ch01Gr1
CurrField =
Ch01Gr2
CurrField =
Ch01Gr3
You can customize the format as you want with sprintf of course.
After pressing the button, here is the content of the handles structure:
LoadButton: 329.0085
Data: [1x1 struct]
Ch01Gr1: [4x1 double]
Ch01Gr2: [4x1 double]
Ch01Gr3: [4x1 double]
Don't forget the good practice of pre-allocating memory, especially if your data is large.
Hope that helped!