MATLAB: Seperating data into matrices based on names

arraycell arraysindexingmatrix manipulation

Hi,
I have a matrix of raw data stored in data.rawdata. Each row corresponds to a measurement which is labeled and the labels are stored at data.label. Labels could be repeated. So I want to seperate the data into different groups based on labels which I have been doing with the followid code:
data.labels=labels;
data.rawdata=rawdata;
groups=unique(data.labels);
for i=1:length(groups);
    measurements{i,:}=data.rawdata((data.labels)==groups(i)),:);
end
I want to use the measurements that are seperated to save tt pp and pr results into seperate cells but brace indexing is not supported for this format inside the brackets… 
for i=1:length(groups)
 [tt{i,:},pp{i,:},pr{i,:}]=pca(measurements{i,:},10); 
end
How can I do the pca calculations on different groups seperately? And how can I store the tt, pp, and pr seperately for different measurement groups?
I could do all this manually but the point is that I want to speed up the calculations by automizing
Another question which is of less importance:
is it possible to save the data in a cell array with different names with a code like: (I know this doesn'T work in the current format'
measurements.gourps(i)=data.rawdata((data.labels)==groups(i)),:);
I am looking forward to answers.
Thanks!

Best Answer

I'm not sure what type do you use for data. Is that a table or a struct? I prefer using table. You can do findgroups first and a splitapply second on data, if it is a table.
[G, res] = findgroups(data(:, "labels"));
s = splitapply(@(x) {pca(x)}, data.rawdata, G);
the result s will be a cell array of length equaling to your number of unique labels.
If you data is a struct, you can use struct2table to convert it to table. prerequisite: data.labels is column vector with length equal to the row of data.rawdata.
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