Merging multiples csv files in Matlab-R2014b

I have 50 csv files without header. Size of each file is 11320x2 with one common column in all files. I would like to merge all of these files in matlab and would like to create a matrix of size (11320x51). Any suggestion is highly appreciated. Thank you!

Answer 1

[Ken Atwell]

Assuming the files are all in the same folder and you have 'cd'ed to there, trying something like:

 files = dir('*.csv');  % Get list of files
 out = csvread(files(1).name);  % First file
 for ii = 2:numel(files)
   new = csvread(files{ii}.name);  % Read the nth file
   out = horzcat(out, new[:,2]);   % Concatenate "out" with the 2nd column from new file
 end

This is from memory and may not be exactly right.

[Mohammed Kamruzzaman]

Hi Ken I firmly believe your code will work. When I tried to run the third line of for loop, i.e. out = horzcat(out, new[:,2]); the following error is coming. It seems everything is ok. But the error is coming. Any suggestions! Error: Unbalanced or unexpected parenthesis or bracket.

[Mohammed Kamruzzaman]

Hi Ken, I modified something and it is working properly. Thanks

[Renjith V Ravi]

Can you please paste the modified code

[Renjith V Ravi]

I am also getting the same error message "Unbalanced or unexpected parenthesis or bracket". Tried a lot to correct but couldn't.Please help me

[Brendan Hamm]

In MATLAB you cannot index with [] as is done in the last line of the for loop. Change this to () and all will work fine.

files = dir('*.csv');  % Get list of files
 out = csvread(files(1).name);  % First file
 for ii = 2:numel(files)
   new = csvread(files{ii}.name);  % Read the nth file
   out = horzcat(out, new(:,2));   % Concatenate "out" with the 2nd column from new file
 end

Answer 2

[Brendan Hamm]

Presumably you would want to use the csvread function. If all of the files are in the same directory, then set that as your working directory. This can be accomplished with

cd [directory]

where [directory] is the full path to your directory.

You can get a list of all of the files in the directory with the dir command.

Answer 3

[Siach Xavisu]

You can merge them with relative ease with http://merge-csv.com even if they got headers.