How can I split a matrix of varying size (depending on data input) into new matrices of 3 columns each?

Basically I start off with a single matrix of arbitrary size (number of columns will be a multiple of 3 as data is XYZ coordinates of points) depending on the data input, and I want to split this matrix into new matrices of x rows by 3 columns each, in order to export the new matrices as single files. The issue is that the number of columns in the initial matrix will vary greatly, so I would prefer not to have to manually change the code to fit the number every data set.

Basically I want to be able to do this but without having to type out each "matrix1", etc:

matrix1 = coordinates(:,1:3);
matrix2 = coordinates(:,4:6);
matrix3 = coordinates(:,7:9);

Thanks in advance, Connor

Answer 1

[dpb]

Sometimes a loop is just as easy as anything else...

i1=1;
for ix=size(xyz,2)/3 % for groups of three
  m=xzy(:,i1:i1+2);  % your group of three
  % do whatever with this set here...
  ...
  i1=i1+3;
end

[Connor McAnuff]

Thanks dpb, I think there's still an issue in that 'm' will be overwritten each time the loop goes through. Even if I export it, I can't change the file name according to the value of 'ix', right?

[dpb]

Well, it's up to you to do whatever you want; if you don't need the subsets simultaneously, there's no point in keeping them around; if you do then you can either use a cell array or other forms to do that depending on the intended use.

Sure you can create a dynamic file name...see the FAQ How_can_I_process_a_sequence_of_files? It's written specifically to read files, but the file name creation and fopen are the same either way excepting for permission and output instead of input.

[Connor McAnuff]

Cool, thanks!