how to read specific columns from several data files stored in a folder.

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MA 2021-9-20

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https://ww2.mathworks.cn/matlabcentral/answers/1456829-how-to-read-specific-columns-from-several-data-files-stored-in-a-folder

评论： MA 2021-9-20

assuming we have a folder that has several data files inside it and the data files are in row/column format, how we can read or extract only specified columns of each file, process them as we need and then move to the next file and so on, rather than reading the whole files.

currently I am using the following code, but it reads the whole file, for effeciency purposes how I can modify this to make the table 't' consists of columns of my choice and not having to read the whole file? or is there a better way to do that?

filePattern = fullfile(myFolder, '*.*'); 
theFiles = dir(filePattern);
theFiles = theFiles(~[theFiles.isdir]);  %remove folders from list
nfiles = length(theFiles);
fullnames = fullfile({theFiles.folder}, {theFiles.name});
results(:,1) = fullnames(:);
for k = 1 : nfiles
  fullFileName = fullnames{k};  
  t = readtable(fullFileName);
end