load data from text file using matrix separator

Question

I am trying to read a text file which contains the data for several matrices and load them in different matrices in matlab. An example of my text file looks like this:

19.623 -15.67 42.995
17.942 -10.923 47.112
23.806 -14.332 49.912
21.582 -11.218 46.203
18.031 -12.567 44.381
15.931 -18.897 39.046
18.497 -17.457 44.327

17.548 -18.604 44.24
15.931 -18.897 39.046
18.43 -16.582 43.091
18.497 -17.457 44.327
16.695 -17.627 39.364
17.548 -18.604 44.24

20.436 -16.416 44.281
17.984 -16.918 44.441
14.703 -17.17 40.697
17.078 -18.111 44.22
16.322 -16.342 38.961
19.582 -18.281 39.937
14.941 -16.27 39.53
18.43 -16.582 43.091

This file represents three matrices where the first, second and third matrices dimensions are 7x3, 6x3 and 8x3 respectively. The matrices are separated using a new line. I have tried using S = LOAD(FILENAME) command but this command creates a 21x3 matrices which is concatenation of all the rows. How can I define a matrix separator (delimiter) for my matrices so it produces different matrices based on different segment of my file? Note that the number of all columns is always 3.

Thanks a million for all your help. I really appreciate it.

Aabaz · Accepted Answer · 2011-09-20 14:37:31Z

2

If you do not have NaN values in your data, you can use textscan with a \n delimiter. It produces NaN values when a blank line is read. Not very elegant but it does the trick. I am sure there are plenty of other ways of doing this.

fid=fopen('data','r');
data=textscan(fid,'%f','delimiter','\n');
fclose(fid);
data=cell2mat(data);
index=find(isnan(data));
A=data(1:index(1)-1);
B=data(index(1)+1:index(2)-1);
C=data(index(2)+1:end);
A=reshape(A,[3 length(A)/3])';
B=reshape(B,[3 length(B)/3])';
C=reshape(C,[3 length(C)/3])';

I must add that if you have any control over how these data files are created you should probably think of changing their format to either one matrix per file or a Matlab mat file.

edited Sep 20, 2011 at 14:37

answered Sep 20, 2011 at 11:55

Aabaz

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Reyhaneh Over a year ago

Thanks for your help. I was thinking of the option creating several files but since I am using these matrices in a loop for an optimization algorithm I thought that creating several files and reading them can increase the runtime. but, I have to look at Matlab mat file. thanks again.

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