Decimated table exporting same size as original

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Taylor Azizeh
Taylor Azizeh 2023-7-17
评论： Taylor Azizeh 2023-8-21
I am trying to decimate a data file that was recorded at 100Hz and the original size of the file is ~6.16GB. I decimated the data by a factor of 2 (to reduce the sample rate to 50Hz), which seems successful:
However, when exported, the size isn't even 1GB less than the original file:
Is my decimation working correctly? Code below.
%%%% Loop to decimate 3 columns (out of 17 total columns)
s = size(data_XYZ);
r = 2;
n = ceil(s(1)/r);
data_XYZ_50 = zeros(n,s(2));
for k = 1:s(2)
data_XYZ_50(:,k) = decimate(data_XYZ(:,k),r);
end
%%%% Extracing every other line from the columns.
data_50 = data(1:2:end,:);
%%%% Replacing the 3 original columns with the decimated data
data_50{:,3} = data_XYZ_50(:,1);
data_50{:,4} = data_XYZ_50(:,2);
data_50{:,5} = data_XYZ_50(:,3);
save_directory = 'G:\path';
table_path = fullfile(save_directory, 'table.csv');
writetable(data_50,table_path)
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Stephen23
Stephen23 2023-8-21
"However, when I exported it as a CSV (this is the format I need), it is the same size."
A CSV file is just an uncompressed text file, why should it be any different?
"Are you saying that if my variable size in MATLAB looks decimated: 83745100/2 = 41872550, then it should be working?"
You could check it yourself: take the first few values, calculate by hand what you expect the "decimated" values to be.
Taylor Azizeh
Taylor Azizeh 2023-8-21
I would just assume that if you have half of the rows of data, logically, your file should be half the size.

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