Read in CSV files using GUI

If I want MATLAB to read in the following file using the GUIDE feature in MATLAB:

Source File:

ID:

C

C

C

C

R

F

L

T

E

Date Time Ch:

03/24/2012 28:43.0 -142.315
03/24/2012 28:43.0 -142.316
03/24/2012 28:43.0 -142.318

and so on,

how can I read the file if the extension is not .csv, say, .pl4?

With a .csv I could use the following but that only assumes if the file .csv which in my case it's not.

fid=fopen('filename.csv');

header = textscan(filenamecsv, '%s',3, 'delimeter' ',','headerLines',16);

data=textscan(filenamecsv, '%s %s %s', 'delimiter', ' ,');

data_to_plot=str2double(data{3});

fclose(filenamecsv);

Answer 1

[Walter Roberson]

fid = fopen('filename.pl4');
header = textscan(fid, '%s', 3, 'headerLines', 16);
data = textscan(fid, '%s %s %f');
data_to_plot = data{3};
fclose(fid);

Answer 2

[T]

But if I create a function:

function openfile_Callback(hObject, eventdata, handles)

[filename,pathname,filterIndex] = ... uigetfile({'*.p4';),['Select the file'],... );

do I still need fid = fopen ?

[Walter Roberson]

Yes.

fullpath = fullfile(pathname, filename);
fid = fopen(fullpath);

[T]

Okay it works, however, when I check each line it appears that after fclose(fid)

[Y,M,D,H,MN,S] = datevec(data{2});

out = H*3600+MN*60+S;

doesn't give me the data in the file. Which is a bit odd. It outputed 2013 when I'm viewing a file from back in 2011.

Do you know what is wrong?

[T]

After fclose. I cannot plot my data

[Walter Roberson]

If you put a breakpoint in at the fclose() line, then can you see your data at that point? But then when you single-step the data is gone? Is the fclose() possibly giving an error that might be causing your function to exit, thereby destroying your function's workspace ?

Or is it perhaps not the fclose() that is the problem, and that the problem is that after the fclose() the function ends and you are trying to plot from a different function? If so then see

http://matlab.wikia.com/wiki/FAQ#How_can_I_share_data_between_callback_functions_in_my_GUI.3F

[T]

I managed to get it working. However, the plot that is created is embedded in the GUI which gets burried underneath the buttons. Is there a way for it to create a new window once plotted?

[Walter Roberson]

You can use figure() to create a new window, and figure() applied to an existing window raises that window to the top.

I recommend you read my comments in http://www.mathworks.co.uk/matlabcentral/answers/22208-show-figure

[T]

I managed to successfully plot after using fclose. However, I have another function, not using say handles.projectdata.data_to_plot

right after for which I can no longer recall that variable. Even if I use :

% Update handles structure

guidata(hObject, handles);

Do you know what I am talking about?

[T]

function openfile_Callback(hObject, eventdata, handles)

[filename,pathname,filterIndex] = ... uigetfile({'*.p4';),['Select the file'],... );

fullpath = fullfile(pathname, filename); fid = fopen(fullpath);

header = textscan(fid, '%s', 3, 'headerLines', 16);

data = textscan(fid, '%s %s %f');

data_to_plot = data{3};

fclose(fid);

using handles.project.data.(then the variable)

f = figure;

ax = axes('Parent',f);

plot(ax,handles.projectdata.time,handles.projectdata.data_to_plot);

grid(ax,'on')

[Walter Roberson]

You have not set handles.projectdata.time or handles.projectdata.data_to_plot in that code.

[T]

Okay. I got it working. Suppose I want the user to plot with this GUI, how can I have the user manipulate the plot by entering certain entries? Is there a reference you can provide? The documentation is long and I would be wasting time going through it all.

In particular, to have the user edit certain values for a variable. So say if x1 = data_to_plot

I want to be able to have the user to multiply x1 by any arbitrary number.

[T]

If you want to use a loading bar when opening files:

function openfile_Callback(hObject, eventdata, handles)

[filename,pathname,filterIndex] = ... uigetfile({'*.p4';),['Select the file'],... );

working = waitbar(0, 'Loading...');

close(working);

How do you get the bar to actually progress? it shows an empty bar but it doesn't show progress.

[Walter Roberson]

You cannot effectively use a waitbar in that situation, as you have no information about how long the load will take, and you are only doing a single operation (that is, a single textscan()).

[T]

suppose it takes 30 seconds? There is the for loop in the documentation for waitbar but it iterates then executes the commands I have after, delaying the processing rather than assessing it.

[Walter Roberson]

If you know how long it will take, use a timer object to update it, and hope that the innards of textscan() are not built-in functions (timers cannot interrupt built-in functions.)