Create a matrix with only the rows indexed by a multiple of N of another matrix.

Hello everyone!

And I am trying to create a matrix, containing only the rows indexed by (1+3x) of a given matrix. In other words, the first row and then jump every 3 rows until the end of the original matrix

Concretely, I have something that looks like this:

x1 = randi([0, 10], [9,2])

x1 =

     5    10
     4     6
     4     5
     2     1
     1     1
     4     8
     9     8
     3     5
     6     6

And I am trying to get this:

     x2 =
     5    10
     2     1
     9     8

Is there any straightforward way to do this?

Thanks!

Answer 1

[David Hill]

x2=x1(1:3:length(x1),:);

Answer 2

[Prasad Reddy]

clc
clear all
x1=randi([0,10],[9,2])
x2=[]
for i=1:3:length(x1)
    x2=[x2; x1(i,:)]
end
% this will work

[TOMAS CARRERA DE SOUZA]

Works indeed. Thanks

[Prasad Reddy]

you can accept my answer also.