xlsread returning empty only sometimes

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Mathieu Lebiere 2018-12-4

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评论： Walter Roberson 2018-12-5

Data.xlsx

I am having trouble with xlsread actually returning values. This code is in a for loop with i as the iterating variable.

sheet = strcat(num2str(i), ' in');
file = 'data.xlsx';
times_data = xlsread(file,sheet,'A3:A402');
Data1 = xlsread(file,sheet,'B3:B402');
Data2 = xlsread(file,sheet,'F3:F402');
Data3 = xlsread(file,sheet,'J3:J402');
Data4 = xlsread(file,sheet,'N3:N402');
Data5 = xlsread(file,sheet,'R3:R402');

In the code above only Data5 has anything stored in it. In the "Workspace" tab everything else is show as empty( with a [] symbol). Does anyone know why this may be and a way to fix it?

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Walter Roberson 2018-12-5

What is your value for i ?

My testing with your file on Mac does not show anything unusual for the sheets that are present.

Mathieu Lebiere 2018-12-5

i goes between 0.5 and 4 in increments of 0.5. It is part of a for loop. I did not get any errors when running the code either on windows.

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Answer 1

Cris LaPierre 2018-12-5

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Any chance you can attach one of your spreadsheets? Much easier to debug that way.

Without seeing that, I'd have two guesses:

Data1-4 and times_data are empty because there is no data in the specified range
The data entered in those ranges is not numeric. In this case, you want to use the [num,txt,raw] = xlsread(___) syntax. You can read more in the xlsread documentation page.

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Cris LaPierre 2018-12-5

编辑：Cris LaPierre 2018-12-5

在 MATLAB Online 中打开

It appears to be #2. If I read the file using the '[num,txt,raw] = xlsread(___)' syntax, the values appear in the txt and raw variables but not num. When I use the import tool, it defaults to text on those columns as well. In fact, only the last 4 columns in sheet '0.5 in' are recognized as numbers.

If I change the format in excel to Number, it does read in the values. However, that may be a bit cumbersome depending on the number of files/sheets to process.

This is where I again recommend readtable. It is also much quicker because you only have to read the file once instead of 6 times for each sheet.

file = 'data.xlsx'; 
opts = detectImportOptions(file);
opts.SelectedVariableNames = [1 2 6 10 14 18];
opts = setvartype(opts,[1 2 6 10 14 18],'double');
opts.VariableNames([1 2 6 10 14 18]) = {'time','Data1','Data2','Data3','Data4','Data5'};
opts.DataRange = '3:402';
[~,sheets] = xlsfinfo(file);
for n = 1:length(sheets)
    data{n} = readtable(file,opts,'Sheet',sheets{n});
end

Mathieu Lebiere 2018-12-5

Much appreciated!

Walter Roberson 2018-12-5

On Mac the values were read properly . That suggests that adding the option 'basic' might have worked on Windows .

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xlsread returning empty only sometimes

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