Do NOT use eval for importing data, unless you intentionally want to force yourself into writing slow, complex, buggy code. Read this to know why:
Instead you should import the data into a matrix, optionally assigning it to one array using indexing, for example using a cell array as the documentation examples show:
Or using the same structure returned by dir:
S = dir('*.txt');
for k = 1:numel(S)
M = dlmread(S(k).name); % better than LOAD.
... do whatever with matrix M, e.g.:
wn = M(:,1); % wavenumber
rn = M(:,2); % rn
...
S(k).data = M; % optional: store any data you want for later.
end
Then you can trivially access the data in that structure, e.g. using loops or indexing:
For example, you can easily vertically concatenate all of the file data together:
alldata = vertcat(S.data);
