# How to store 2D variables in matrix

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Ni2 on 27 Oct 2019
Commented: Ni2 on 27 Oct 2019
I want to have a variable which can store coordinates of various "N" points.
Then i want to randomly select "n" number of the points without repetition.
n<=N

Bjorn Gustavsson on 27 Oct 2019
For the storing the point coordinates you might look at either cell-arrays:
r1 = [1,2,3];
r2 = [3,2,5];
r3 = [4.5,pi,1,5]; % if some of your point-coordinates are of different sizes
Point_array = {r1,r2,r3} ; % and so on
or simply a higherdimensional array:
r1 = [1,2,3];
r2 = [3,2,5];
r3 = [4.5,pi,1]; % if some of your point-coordinates are of different sizes
Point_array(:,3) = r3;
Point_array(:,2) = r2;
Point_array(:,1) = r1; % and so on
For the selection of n points out of that one, have a look at the file exchange for: nextchoose and nextperm. They solve most of my problems with tasks like that.
HTH

#### 1 Comment

Ni2 on 27 Oct 2019
I what to store 6 points in A, then again i wanna store "n" points in A using while loop. How can i do that ??