How to manipulate a series of .csv files after reading it inside a for loop?

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JOYA GHOSH DASTIDER 2022-2-8

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评论： JOYA GHOSH DASTIDER 2022-2-8

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I am trying to read a series of.csv files and then trying to extract a particular row depending on a specific value of 1st 2 columns and then writing that particular row in another .csv file. That specific row has to be extracted from each of the input files and then the output file should contain all the extracted rows. But in my code , it is taking only the last file of the series. How can I get it for all the input files? I am attaching a pic of my code. Thank you.

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JOYA GHOSH DASTIDER 2022-2-8

sample files:

JOYA GHOSH DASTIDER 2022-2-8

I was checking at different steps inside the loop. The three iterations were going on but atlast the file variable takes only the last file from data cell and execute the operation.

I am new in MATLAB. So not sure if I am using proper syntex or there may be some problem with indexing.

first the data cell storing all the .csv files in it . then I am trying to get data{i} in file variable in each iteration and to extract that one row and write it in a separate output file.

so after completing the whole loop, the output file should contain all the extracted rows in it.(example:3 rows for three input files and column same as the no of columns in the input file.)

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Answer 1

DGM 2022-2-8

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1645655-how-to-manipulate-a-series-of-csv-files-after-reading-it-inside-a-for-loop#answer_891530

在 MATLAB Online 中打开

sorted.txt

It seems to be picking up and writing all three lines to the file. The output formatting is messed up, but it's all there.

I edited the fprintf() call:

d = dir('*_rain.csv');
n = length(d);
data = cell(n,1);
for i = 1:n
    data{i} = csvread(d(i).name,1,0);
    file = data{i};
    
    ind1 = file(:,1) == 91.75 & file(:,2) == 26.25;
    a = file(ind1,:);
    
    fid = fopen('sorted.txt','a+');
    fprintf(fid, [repmat('%f, ',1,11) '%f\n'],a.');
    fclose(fid);
end