hi every one , how can i do a for cycle with diffrent vector length , thank you

clear all 
clc
X=rand(17,1) 
Y=rand(31,1)
Z=rand(28,1)
K=rand(31,1) 

n=31 
for i=1:n
    A=[X(:,n) , Y(:,n) ,Z(:,n) ,K(:,n)];
    AT{1,n}= inv(A{1,n}'*A{1,n})*A{1,n}';
end

[Rik]

What do you mean? You aren't using standard Matlab terms, nor are you describing any errors, nor what your goal is. Have a read here and here. It will greatly improve your chances of getting an answer.

I do notice that your vectors have different lengths, yet you want to put them together? What should A look like when n is 18? Should it be a 3-element vector?

And why are you selecting all rows and non-existant later columns for n>1? And why are you using curly braces on a non-cell array?

[mina massoud]

sorry if first i didnt explain well my problem ,

i mean that i need to calcolate AT in this condition with a cycle for :

1) for the first 17 cycle i need to calcolate AT for all X Y Z K

2) from 18 to 28 in need to calcolta AT for Y Z K

3) from 29 till the end i need to calcolate only for Y K

thank you for your time

Answer 1

[Rik]

You can put them in a cell array and let cell2mat handle the removal of empty elements. I have no clue what you want to do with that variable inside your loop, so I replaced it with sum to have a proof of principle. (also, no need for clear all)

X=rand(17,1);
Y=rand(31,1);
Z=rand(28,1);
K=rand(31,1);

A=cell(numel(X),4);
A(1:numel(X),1)=num2cell(X);
A(1:numel(Y),2)=num2cell(Y);
A(1:numel(Z),3)=num2cell(Z);
A(1:numel(K),4)=num2cell(K);

AT=zeros(1,size(A,1));
for n=1:size(A,1)
    B=A(n,:);B=cell2mat(B);
    AT(n)= sum(B);
end

[mina massoud]

thank you ,