Horizontally concatenate existing CSV columns

Question

Constance Woodman 2017-7-15

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/348875-horizontally-concatenate-existing-csv-columns

编辑： ANNE NDJALI 2019-3-9

采纳的回答： Star Strider

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I have files in a directory, the directory location is saved to a variable called hardCodeFilePath

Within the directory hardCodeFilePath, there are five CSV files.

Each CSV is a single column of numerials WITH A STRING HEADER, which drives me mad as it creates a mixed data type.

Due to this mixed data type I can't just save them to numerical arrays and fiddle with them that way. (Blast!)

I saw a neat solution for joining multiple columns frOm mixed data type CSV files into a single mega-column but I am too much an idiot to make this join them horizontally in five columns instead of one vertical mega-column.

Here is that solution:

        function    ccsm()
sad = dir( 'x*.csv' );                             % 1
        % Is the order of the files important?               
        fid_out = fopen( 'concatenated_files.csv', 'w' );  % 2 
        for jj = 1 : length( sad )                         % 3
            fid_in = fopen( sad(jj).name, 'r' );           % 4 
            str = transpose( fread( fid_in, '*char' ) );   % 5 
            fclose( fid_in );                              % 6 
            if not( jj == 1 )                              % 7
                ix1 = regexp( str, '[\r\n]++', 'once' );   % 8 
                str = str(ix1:end);                        % 9
            end
            ix2 = regexp( str, '[\r\n]++$', 'once' );      % 10
            if not( isempty( ix2 ) )                       % 11
                str(ix2:end) = [];                         % 12
            end
            fwrite( fid_out, str, '*char' );               % 13 
        end
        fclose('all');                                     % 14       
    end

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Answer 1

Star Strider 2017-7-15

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https://ww2.mathworks.cn/matlabcentral/answers/348875-horizontally-concatenate-existing-csv-columns#answer_274275

If you have R2013b or later, and if your ‘.csv’ files all have the same number of rows, I would read each of them in separately with the readtable (link) function, and then horizontally concatenate the tables.

You can then save the concatenated table as a single table to another file using the writetable function.

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Constance Woodman 2017-7-15

Why, what a jolly good solution!!

Here is working script to implement that solution in case someone wants to try it!

colA = readtable('lowdataS1Roll1Hour.csv') colB = readtable('lowdataS1Yaw1Hour.csv')

fluttershy = horzcat(colA,colB)

writetable(fluttershy,'mergedCols.csv')

Star Strider 2017-7-15

Thank you!

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Answer 2

ANNE NDJALI 2019-3-9

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/348875-horizontally-concatenate-existing-csv-columns#answer_364606

编辑：ANNE NDJALI 2019-3-9

I have a similar problem, but my .csv files are not all the same number of rows. Is there a funciton that would work like the readtable + horzcat + writetable?

Thank you!