How can I write an excel file using the timer on MATLAB?

I'm trying to write data to excel only once at the end using a timer on MATLAB.

There are two things I want to do :

1) When I execute the program which I written referring to the sample code below, I get an error and I have no idea how to fix the error.

2) Currently, the values ​​of x_value and y_value are displayed without using the disp () function, but I want to prevent this from being displayed.

Error message

>> timer_sample

x_value =

     1     2     3


y_value =

     4     5     6


x_value =

     1     2     3     7     8     9


y_value =

     4     5     6    10    11    12

Error while evaluating TimerFcn for timer 'timer-1' 

Error: Invalid expression. Check for missing multiplication operator, missing or unbalanced delimiters, or other syntax error. To construct matrices, use brackets instead of parentheses.

Program which I executed

global x_value
global y_value

time = timer('TimerFcn', 'stat=false; disp(''Timer!'') filename = ''data.xlsx''; x_range = ''sender''; y_range = ''receiver''; xlswrite(filename, x_value, x_range) xlswrite(filename, y_value, y_range) exit();', 'StartDelay', 30);
start(time)

%flag to write code after 30 seconds
global stat
stat = true;

x_value = [x_value [1 2 3]] 
y_value = [y_value [4 5 6]]

x_value = [x_value [7 8 9]] 
y_value = [y_value [10 11 12]]

What I tried to

Without the time, I am sure that excel output is available like the below.

global x_value
global y_value

global stat
stat = true;

x_value = [x_value [1 2 3]]
y_value = [y_value [4 5 6]]

x_value = [x_value [7 8 9]]
y_value = [y_value [10 11 12]]

filename = 'data.xlsx';
x_range = 'sender';
y_range = 'receiver';
xlswrite(filename, x_value, x_range) 
xlswrite(filename, y_value, y_range) 

[Adam]

That's an absolutely horrible way to define a function (multiple lines all in a single string). It would be much easier for you to see what is wrong (and more readable, less brittle in general) to just define it as a function and pass the handle to that function in. Nevertheless, without trying it, I suspect you are simply missing the ; off the end of disp(''Timer!'') in the function string and also later on after the first xlswrite.

You are also missing ; off the end of your x_value and y_value lines which is why they print to the command line.

I would also strongly advise against using global variables, there is pretty much nothing that can't be done better with just proper variables passed around between functions as arguments.

[Jan]

Adam hits the point.

XLSX files are zipped files. They are a very bad choice for appending data dynamically, because the unpacking and repacking requires an exponentially growing amount of time. Prefer appending data to a binary or text file and convert the data at the end to an XLSX file.

Answer 1

[Guillaume]

As others have said, defining the timer function as a string is the worst way of doing it. You get no syntax highlighting, no tab completion, no way of debugging code. It's a recipe for bugs, as your case proves. So define that timer callback as a proper function.

Personally, since you also want to pass data to that callback, I'd go OOP and wrap that in a class. This also avoids the dreaded global variables:

classdef TimerCallback < handle
    properties  %public properties
        state;
        x_value;
        y_value;
        filename;
    end
    methods
        %constructor
        function this = TimerCallback(filename)
            if nargin > 0
                this.filename = filename;
            end
            this.state = true;
        end
    
        %callback function
        function callback(this, ~, ~)
            %consider using writetable instead of xlswrite. At least, use only one xlswrite.
            xlswrite(this.filename, this.x_value, 'sender');
            xlswrite(this.filename, this.y_value, 'receiver');
            this.state = false;
            disp('Callback executed');
        end
    end
end

Your script is then:

mycallback = TimerCallback('data.xlsx');
mytimer = timer('TimerFcn', @mycallback.callback, 'StartDelay', 30);
start(mytimer);
mycallback.x_value = [mycallback.x_value, [1 2 3]];
mycallback.y_value = [mycallback.y_value, [4 5 6]];
mycallback.x_value = [mycallback.x_value, [7 8 9]];
mycallback.y_value = [mycallback.y_value, [10 11 12]];
%and so on... until the Timer completes

[horizon]

Thank you for your answer. How can I go OOP? I would like to add the callback function to 'classdef TimerCallback' but only I can see my script on MATLAB.

[Guillaume]

OOP = object oriented programming. I.E. use classes, which is what I've done with my answer.

So you'd save the classdef code into its own file (Timercallback.m) and use it as I've shown with the script. That is you create an instance of the class (an object) which will store the x_value and y_value. Associated with the class, there is a callback method which is what you pass to the timer.

[horizon]

Thank you for your reply.

I've executed timer_sample.m and TimerCallback.m is located on the same folder with timer_sample.m.

However, I got the following error message.

How can I fix it and what is the problem?

Error Message

>> timer_sample
Attempt to execute SCRIPT varargin as a function:
/Applications/MATLAB_R2019a.app/toolbox/matlab/lang/varargin.m
Error in TimerCallback (line 11)
            if varargin > 1
Error in timer_sample (line 1)
mycallback = TimerCallback('data.xlsx');

timer_sample m

mycallback = TimerCallback('data.xlsx');
mytimer = Timer('TimerFcn', @mycallback.callback, 'StartDelay', 30);
mycallback.x_value = [mycallback.x_value, [1 2 3]]
mycallback.y_value = [mycallback.y_value, [4 5 6]]
mycallback.x_value = [mycallback.x_value, [7 8 9]]
mycallback.y_value = [mycallback.y_value, [10 11 12]]
%and so on... until the Timer completes

TimerCallback m

classdef TimerCallback < handle
    properties  %public properties
        state;
        x_value;
        y_value;
        filename;
    end
    methods
        %constructor
        function this = TimerCallback(filename)
            if varargin > 1
                this.filename = filename;
            end
            this.state = true;
        end
    
        %callback function
        function callback(this, ~, ~)
            %consider using writetable instead of xlswrite. At least, use only one xlswrite.
            xlswrite(this.filename, this.x_value, 'sender');
            xlswrite(this.filename, this.y_value, 'receiver');
            this.state = false;
        end
    end
end

[Guillaume]

Yes, there were several typos. I've fixed them all. This particular error was because varargin was meant to be nargin (and the comparison should have been against 0 not 1).

[horizon]

I have no windows environment now and executed your code on Mac.

I've got the following result and any excel file was not created.

Should I try it on Windows environment?

>> timer_sample
Warning: Unable to write to Excel format, attempting to write file to csv format. To write to an Excel file, convert your data to a table and
use writetable. 
> In xlswrite (line 179)
  In TimerCallback/callback (line 20)
  In timer_sample>@(varargin)mycallback.callback(varargin{:})
  In timer/timercb (line 34)
  In timercb (line 24) 
Warning: Unable to write to Excel format, attempting to write file to csv format. To write to an Excel file, convert your data to a table and
use writetable. 
> In xlswrite (line 179)
  In TimerCallback/callback (line 21)
  In timer_sample>@(varargin)mycallback.callback(varargin{:})
  In timer/timercb (line 34)
  In timercb (line 24) 
Callback executed

[Guillaume]

Yes, as documented xlswrite can only write excel files on a Windows computer with Excel installed.

On a MAC, you can use writetable, or since R2019a, writematrix to write excel files on non-windows computers.