How to import data from external file to Matlab when a format repeats N times inside the file?

Dear all,

I have a lot of files with the following format inside:

First Line: title; Second line: subtitle; then, a MxN matrix.

Example:

 # Detector n:            1   Det1Name     (integrated over solid angle)
 # N. of energy intervals         500
  1.000E-06  1.030E-06  0.000E+00  0.000E+00
  1.030E-06  1.061E-06  1.000E+00  0.000E+00
  1.061E-06  1.094E-06  0.000E+00  0.000E+00
  1.094E-06  1.127E-06  3.000E+00  0.000E+00
  1.127E-06  1.161E-06  4.000E+00  0.000E+00
  1.161E-06  1.196E-06  2.000E+00  0.000E+00
  1.196E-06  1.232E-06  1.000E+00  0.000E+00
  (...)

 # Detector n:            2   Det2Name    (integrated over solid angle)
 # N. of energy intervals         500
  1.000E-06  1.030E-06  0.000E+00  0.000E+00
  1.030E-06  1.061E-06  1.00E+01  0.000E+00
  1.061E-06  1.094E-06  3.000E+01  0.000E+00
  1.094E-06  1.127E-06  9.000E+00  0.000E+00
  1.127E-06  1.161E-06  1.200E+00  0.000E+00
  1.161E-06  1.196E-06  1.400E+00  0.000E+00
  1.196E-06  1.232E-06  1.200E+00  0.000E+00
  (...)
(...)

So, How to import this file to MATLAB in order to get matrix like Det1(M,N), Det2(M,N), etc?

If I had just one table for each file, I could use importdata(). But, what about this case?

Answer 1

[Titus Edelhofer]

Hi,

you can use textscan for this task:

% open the file
fid = fopen('yourfile.txt', 'rt');

% read the first header line, discard or do what ever you like with it
firstHeader = fgetl(fid);

% read the second header line and get the number of rows:
secondHeader = fgetl(fid);
tokens = textscan(secondHeader, '%s');
rows = str2double(tokens{1}{end});

% read the data
aData = textscan(fid, '%g', 4*rows);
data = reshape(aData{1}, 4, rows)';

and then you continue to do this in a loop (with result data{iLoop} = reshape(aData...) until you reach the end of the file (e.g. firstHeader is 0 instead of a string.

Titus

[Marlon Saveri Silva]

Titus,

Thank you too much; perfect answer; it would take me days to find it by myself