## Hi everyone ! can anyone help me to do this , thank you

### mina massoud (view profile)

on 14 May 2019
Latest activity Commented on by mina massoud

### mina massoud (view profile)

on 14 May 2019

% I'd like to take the first 4x4 block of X and put it in Xa and Xb
% in such a way as to take the first and second column of X and put it in the first and second column in Xa
% and take the third column and the fourth column of X and put it in the third and fourth column of Xb
% second block 4x4 of X
% the (5,6) column of X in the (5,6) column of Xa
% the (7,8) column of X in the (5,6) column of Xb
clear all
clc
P=2;
M=4;
X=rand(M,P*M);
Xa=zeros(M,P*M);
Xb=zeros(M,P*M);

Fangjun Jiang

### Fangjun Jiang (view profile)

on 14 May 2019
double check all the column numbers in your question and make sure they are correct.
mina massoud

### mina massoud (view profile)

on 14 May 2019
yes you are wright becasue at the end i need to make somthing like this for P=4:-
Xa(:,1:2)= X(:,1:2)
Xb(:,3:4)= X(:,3:4)
Xa(:,5:6)= X(:,5:6)
Xb(:,7:8)= X(:,7:8)
Xa(:,9:10)= X(:,9:10)
Xb(:,11:12)= X(:,11:12)
Xa(:,13:14)= X(:,13:14)
Xb(:,15:16)= X(:,15:16)
so can i do it with somthing more general , thank u

### Release

R2019a

on 14 May 2019

on 14 May 2019

[~,n]=size(X);
xai=[1:4:n,2:4:n];
xbi=[3:4:n,4:4:n];
Xa(:,xai)=X(:,xai)
Xb(:,xbi)=X(:,xbi)

Fangjun Jiang

### Fangjun Jiang (view profile)

on 14 May 2019
this would be my guess. n=size(X,2), sort() is not needed.