Need to extract a piece of data from hundreds of files

Hello,

I have hundreds of files. I need a specific piece of data from each of them. I then need to insert this data into another set of files.

I know I need to use xlsread and write. My question is: is there a way to automate Matlab opening each file? It's enough files that it would take too much effort to put each file path in an array or something.

I've been reading about dir, but i'm not sure that's what I need.

Are there any resources that could help me?

Thanks!

Answer 1

[Krithika A]

I use dir for my text files, so for me I would do this:

files = dir('file*.txt'); % Extracting all text files that start with "file", e.g., file1, file2, etc.
x = []; % Use to put entire dataset into one matrix
for q = 1:length(files);
    data = importfileB(emoB(q).name, 2, 15361); % importfileB is function I created using the import tab in matlab, you might find it useful for your excel files
    eval(['x',num2str(q),'=data;']) % Use this if you want each data set seperately
    x_raw = [x, data(:,1)]; % Or you can use this if you'd like your entire data set in one matrix
end

For specific excel help, go here: https://uk.mathworks.com/matlabcentral/answers/222871-reading-multiple-excel-files#answer_181883

[Stephanie M]

This should help! Actually, would you also mind sharing your importfileB function as well?

[Krithika A]

No problem! So my import function is specific to my data that I am extracting. It would be better if you create it yourself, but this is very easy to do. Go to the home tab on matlab and click "import data". Click the one of the files you want open (assuming all your files have a similar structure). Then you'll get a window where you can choose the specific dataset you want. Once you're happy, click the drop down button labelled" import selection" in the top right corner of the window. Choose "generate function", and matlab will produce the code you want.

[Stephanie M]

Oh cool! Thank you! Also, what is emoB()?

[Krithika A]

Oh sorry, I left that part in. That's just the way I want matlab to label my data. You can rename to whatever.

[Stephanie M]

Awesome, thanks!