To remove elements from a matrix and convert into single column

Hi,

I have one problem with the removal of elements in a matrix, say I have the matrix of 3*3 as

7 8 9;
4 5 6;
1 2 3

I want to extract only 1 2 3 and 7 8 9 nos and that too these should be in a single column as

1
2
3
7
8
9

And also this is in for loop with i = 1:9

How can I do this inside the for loop?

Thanks and Regards,

Sunag R A.

Answer 1

[KSSV]

Why loop you can straight away extract what you want:

A = [7 8 9; 4 5 6; 1 2 3] ;
% without loop
iwant = [A(end,:) A(1,:)] ;

Read about matlab indexing: https://www.mathworks.com/company/newsletters/articles/matrix-indexing-in-matlab.html

Answer 2

[Sunag R A]

Thank you very much for the answer. But say I have values like this, for i = 1: 9 in columns like this (1;2;3;4;5;6;7;8;9) I am taking loop because the no's may exceed to 100's later.So.

How to extract the same no's in a single column like deleting 4,5 and 6 nos?

Thanks and Regards,

Sunag R A.

[KSSV]

You can remove / delete 4,5,6 which falls in second row using

    A = [7 8 9; 4 5 6; 1 2 3] ;
    A(2,:) = [] 

To check with many numbers, you  have to give conditions, like what numbers you want to delete/ remove. 

A = [7 8 9; 4 5 6; 1 2 3] ;
% remove 4,5,6
[m,n] = size(A) ;
B = A ;
for i = 1:m
    if any(A(i,:) >=4 & A(i,:)<=6)
        B(i,:) = [] ;
    end
end
% arrange B in column 
iwant = sort(B(:))';