parse text file in MATLAB

Question

How can I parse file in MATLAB? The data in the text has this format:

p
15.01245  20.478
12.589  58.256
n
16.589  87.268
52.367  46.256
2.589  58.02

I want to store each data in separate array (i.e; store data under letter p in array 1, and data under letter n in array 2).

any help?

Answer 1

You can do this by using fgets to read in the file line by line and checking for lines containing p and n.

fid = fopen('pn.txt'); % open the file
i2 = 1;
data = {};
while ~feof(fid) % loop over the following until the end of the file is reached.
      line = fgets(fid); % read in one line
      if strfind(line,'p') % if that line contains 'p', set the first index to 1
          i1 = 1;
      elseif strfind(line,'n') % if that line contains 'n' set the first index to 2
          i1 = 2;
      else
          data{i1,i2} =  str2num(line); % otherwise, it the line contains numbers, add them to a cell array.
          i2 = i2 + 1;
      end
end
fclose(fid);

%convert the cell array into two matrices.
p = cell2mat(data(1,:));
p = reshape(p,[numel(p)/2,2])
n = cell2mat(data(2,:));
n = reshape(n,[numel(n)/2,2])