Subscripting into a table using one subscript (as in t(i)) is not supported. Specify a row subscript and a variable subscript, as in t(rows,vars). To select variables, use t(:

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Shawn Berry
Shawn Berry on 13 Mar 2022
Commented: Peter Perkins on 15 Mar 2022
Hello, I am new to MATLAB. I am using the example of forecasting a sequence using deep learning by adapting the code from this example:
I am getting an error that suggests I use a subscript on the part of the code where data is trained. I placed a line underneath where I read in the data, thinking this would suffice. I am not sure why MATLAB is expecting something more for the part where you allocate training and test datasets.
data = readtable('numfile.xlsx')
data(5572,1)
numObservations = numel(data);
idxTrain = 1:floor(0.9*numObservations);
idxTest = floor(0.9*numObservations)+1:numObservations;
dataTrain = data(idxTrain);
dataTest = data(idxTest);
The error appears to be highlighting dataTrain. Why would this error occur? I'm using the same code but a different data file.
Thank you.

Accepted Answer

Voss
Voss on 13 Mar 2022
The error seems to be happening because data is a (scalar) table, but the rest of the code was written to expect data to be an array of numbers.
You can try getting the data out of the table and using that:
data = readtable('numfile.xlsx')
data = data{:,1}; % get the first column of data from the table 'data'. store it as 'data'.
numObservations = numel(data);
idxTrain = 1:floor(0.9*numObservations);
idxTest = floor(0.9*numObservations)+1:numObservations;
dataTrain = data(idxTrain);
dataTest = data(idxTest);
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More Answers (2)

yanqi liu
yanqi liu on 14 Mar 2022
data = xlsread('numfile.xlsx')
data(5572,1)
numObservations = size(data, 1);
idxTrain = 1:floor(0.9*numObservations);
idxTest = floor(0.9*numObservations)+1:numObservations;
dataTrain = data(idxTrain,:);
dataTest = data(idxTest,:);

Peter Perkins
Peter Perkins on 14 Mar 2022
As the error message suggests, all you need is a colon as the second subscript.
data = readtable('numfile.xlsx')
...
dataTrain = data(idxTrain,:);
dataTest = data(idxTest,:);
If the data are one column vector (which seems unlikely since you are doing deep learning), use readmatrix instead of readtable, and then you can use just one subscript.
  2 Comments
Peter Perkins
Peter Perkins on 15 Mar 2022
If you are using someone else's code that expects a table, then you need to use tables, even if you only have one variable. It sounds like you are in that situation. "Someone else" might be The MathWorks, and if that's the case I recommend that you read the doc for whatever functions you are using.

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