How can I combine multiple excel files in a single new excel file?

I have 500 csv files that are saved in specific folder with names are [longshore1.csv,longshore2.csv, ..... longshore500.csv]. Each file contain single sheet with 3 columns data. I need to combine all these 500 files to three single file with merge every column data. As for example, Suppose longhore1=[1 2.3 0.10; 2 2.8 0.11; 3 3.2 0.08;...] longhore2=[6 2.5 0.17; 3 2.1 0.14; 6 4.8 0.05;...]. I want to save longshore_f1.csv=[1; 2; 3; ...6; 3; 6;...], longshore_f2.csv=[2.3; 2.8; 3.2; ...2.5; 2.1; 4.8;...] and longshore_f3.csv=[0.10; 0.11; 0.08; ...0.17; 0.14; 0.05;...].

Answer 1

[Walter Roberson]

fid_out1 = fopen('longshore_f1.csv', 'wt');
fid_out2 = fopen('longshore_f2.csv', 'wt');
fid_out3 = fopen('longshore_f3.csv', 'wt');

for K = 1 : 500
  filename = sprintf('longshore%d.csv', K);
  data = xlsread(filename);
  fprintf(fid_out1, '%g\n', data(:,1));
  fprintf(fid_out2, '%g\n', data(:,2));
  fprintf(fid_out3, '%g\n', data(:,3));
end

fclose(fid_out1);
fclose(fid_out2);
fclose(fid_out3);

[Dipankar Kumar]

Thanks Walter Roberson.