Writing in an existing Excel file
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Giulia Pötgens
on 28 Jul 2021
Answered: Ananya Tewari
on 10 Aug 2021
I am making a GUI with the AppDesigner in Matlab. The app needs to be able to run multiple times, each time the results need to be published in the same Excel file. Except, when running the app again, the data in the Excel is lost and only new data added to the file, even when manually saving the Excel file. These are my callbacks:
Does anyone know why it is not overwriting the existing Excel file?
% Callbacks that handle component events
methods (Access = private)
% Value changed function: SamplenumberEditField
function SamplenumberEditFieldValueChanged(app, event)
value = app.SamplenumberEditField.Value;
end
% Button pushed function: StartButton
function StartButtonPushed(app, event)
ind = app.SamplenumberEditField.Value;
filename = 'Format.xlsx';
table_starttimes = cell(100,1);
table_starttimes{ind} = datestr(now, 'HH:MM:SS');
xlswrite('Format.xlsx',table_starttimes,'Sheet1','F2')
end
% Button pushed function: SnapshotButton
function SnapshotButtonPushed(app, event)
im = imread('image.tif');
ind = app.SamplenumberEditField.Value;
filename = 'Format.xlsx';
table_sample = cell(100,1);
table_name = cell(100,1);
table_amount = cell(100,1);
table_conc = cell(100,1);
table_endtimes = cell(100,1);
table_volume = cell(100,1);
table_inside = cell(100,1);
table_outside = cell(100,1);
table_sample{ind} = ind;
table_name{ind} = 'name';
table_volume{ind} = 2;
table_inside{ind} = 2;
table_outside{ind} = 2;
%% Save endtime and concentration to excel file
amount=f_calculate()
binder_concentration=amount/2
table_amount{ind} = amount;
table_conc{ind} = binder_concentration;
table_endtimes{ind} = datestr(now,'HH:MM:SS');
xlswrite('Format.xlsx',table_name,'Sheet1','A2')
xlswrite('Format.xlsx',table_sample,'Sheet1','B2')
xlswrite('Format.xlsx',table_volume,'Sheet1','C2')
xlswrite('Format.xlsx',table_outside,'Sheet1','D2')
xlswrite('Format.xlsx',table_inside,'Sheet1','E2')
xlswrite('Format.xlsx',table_endtimes,'Sheet1','G2')
xlswrite('Format.xlsx',table_amount,'Sheet1','H2')
xlswrite('Format.xlsx',table_conc,'Sheet1','I2')
winopen('Format.xlsx')
end
end
2 Comments
dpb
on 28 Jul 2021
"when running the app again, the data in the Excel is lost and only new data added to the file, even when manually saving the Excel file. These are my callbacks:..."
"Does anyone know why it is not overwriting the existing Excel file?"
Those two statements are contradictory.
Please clarify which is the desired result -- and what, specifically is wrong are you seeing that isn't as desired?
It surely looks as though the above would insert all new data into the same file at the same locations each time it is run.
I would, however, strongly recommend to restructure your code to put the data into a column array and write the array once instead of calling xlswrite multiple times--this is a real bottleneck and unnecessary.
Also, use writematrix instead of the deprecated xlswrite
Accepted Answer
Ananya Tewari
on 10 Aug 2021
Hi,
It is recommended to use writematrix instead of xlswrite. By default The writematrix function overwrites any existing file. So you need to set the WriteMode property as append to actually add data to a existing file and not overwriting it. Here is the example code for the same. Refer to this link for more information.
M1 = magic(5)
M2 = [5 10 15 20 25; 30 35 40 45 50]
writematrix(M1,'M.xls')
writematrix(M2,'M.xls','WriteMode','append')
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