how to add colmun to vector

hello how can i add to my colmn vector using for loop ?

for exmaple i have this vector [0;0] and i want it to grow by one and keep adating like this for exmaple [0 1;0 1] and then [0 1 2; 0 1 2] and then [0 1 2 3; 0 1 2 3 ] and so on

[Guillaume]

Note that growing arrays in a loop is not recommended. It adversely affects performance. Preallocation and indexing is recommended instead.

Answer 1

[Torsten]

help horzcat

Best wishes

Torsten.

[tomer polsky]

thankes for the help but i want to do it using for loop

[Torsten]

mat = [0;0];
id = ones(2,1);
n = 4;
for i=1:n
  mat = horzcat(mat,i*id);
end

Best wishes

Torsten.

[tomer polsky]

thank you very much is there any other way without using horzcat command ?

[Torsten]

mat = [mat,i*id];

Best wishes

Torsten.

Answer 2

[tomer polsky]

clc;
clear all;

x=[0;0]
for i=1:5
   x(:,i)=i
end

your wat is too complicated ,here is the way i found

[Guillaume]

Torsten's way may be too complicated but it certainly performs better than the above. In particular, in the first step of the loop, the above replaces

x = [0;0]

by

x = [1;1]

The next steps of the loop do indeed grow x (not recommended) so the end result is:

x = [1 2 3 4 5; 1 2 3 4 5]

not

x = [0 1 2 3 4;0 1 2 3 4]  %or maybe [0 1 2 3 4 5;0 1 2 3 4 5]

as was requested

Answer 3

[Guillaume]

And the proper way is to use preallocation instead of growing the array:

 numsteps = 5;  %and not using hardcoded ends for loops
 x = zeros(2, numsteps);
 for i = 1:numsteps
   x(:, i) = i-1;
 end