How do I concatenate the data to plot multiple spectra in one graph

So I have been trying to import 167 .csv files from a directory. These files should be plotted together (j vs w) and I would like to concatenate all the j (dims 2204x1) values as a matrix. The first column should be w (dims 2204x1), which is constant for all the files and the rest should be the 167 'j' values. So far I've been successful at reading all these files, but I cannot build a matrix (I also can't plot these). I chose the row values "15:end" because there is no data prior to this.

I've been combing through the forums and I can't seem to find the right code to do this. I've tried using brackets and curly brackets.

Any help would be appreciated!

    a=dir('*.csv');

    for i=1:length(cell(size(a)))
    bob = sprintf('_ (%i).csv',i)
    [~,~,idx{i}]=xlsread(bob);
    w=table(idx(:,1));
    j=table(idx(:,2));

    w=w{15:end,'Var1'};
    j=j{15:end,'Var1'};

    end

Answer 1

[Walter Roberson]

    a = dir('*.csv');
    numfiles = length(a);
    for i = 1 : numfiles
      bob = sprintf('_ (%i).csv',i)
      [~,~,idx]=xlsread(bob);
      if i == 1
        w = idx(15:end,1));
        j = zeros(size(w,1), numfiles);
      end
      j(:,i) = idx(15:end,2);
   end

[Amanda Figueroa]

Thanks Walter,

I ended up modifying this code since xlsread did not read the data I wanted. I really appreciate your help

   a = dir('*.csv');
    numfiles = length(a);
    for i = 1 : numfiles
      bob = sprintf('_ (%i).csv',i)

      data(i)=importdata(bob)

    plot(data(i).data(:,1),data(i).data(:,2))
    hold on
     if i==1
        w = data(i).data(1:end,1);
        j = data(i).data(1:end,2);
     end
      j(:,i) = data(i).data(1:end,2);
    end

    hold off
    xlabel('Wavenumber (cm^-^1)')
    ylabel('Reflectance')