Append rows at the end of Matrix

Hi,

a = [1 2 3 ; 4 5 6; 7 8 9]; --> 3x3 matrix

I want to insert at the end number of raws with same elements such as [5 5 5] and make the matrix 10 x 3 i.e. I want to insert 7 more raws with [5 5 5]. Please explain.

Answer 1

[Azzi Abdelmalek]

a = [1 2 3 ; 4 5 6; 7 8 9];
b=[5 5 5]  
c=[a;b]% add one row
c=[a;repmat(b,7,1)]  %add 7rows

[Trushit]

Thanks a lot. The answer also helps when we have different elements in stead of all same.

[shubham shinde]

What if I have to insert the row somewhere between middle of the original matrix? Thank you in advance.

[Hugh]

Yes, a long-time-after answer to a long-time-after question, but why not?

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

Or for a bit more malleable solution (variable row to add to):

a = [1 2 3; 4 5 6; 7 8 9];
b = [5 5 5];
addrow = 2;
a = [a(1:addrow-1,1:3);b;a(addrow:3,1:3)]

Or a bit prettier, and even more malleable (if a has variable number of rows):

a = [1 2 3; 4 5 6; 7 8 9];
b = [5 5 5];
addrow = 2;
a = [a(1:addrow-1,:);b;a(addrow:end,:)]

[jerrell lim]

is there a way to create a matlab matrix 5 by 5 in one command without typing each number individually ?

the numbers are [0 0 0 0 0;0 0 0 0 0;0 0 1 2 3; 0 0 4 5 6; 0 0 7 8 9]

[user924]

Perhaps try creating a 5x5 matrix of zeros and using a for loop to overwrite the elements that you want to be non-zero.

a =

0 0 0 0 0

0 0 0 0 0

0 0 1 2 3

0 0 4 5 6

0 0 7 8 9

a = zeros(5);
b = [1:9];
width = 3;
[m,n] = size(a);
for row = m:-1:1
    for col = n:-1:n-2
        if size(b) > 0
            a(row, col) = b(end);
            b = b(1:end-1);
        end
    end
end
a

Answer 2

[Amit]

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

[Trushit]

Thank you. It's short and speedy.

Answer 3

[Michael Hawks]

Another method:

a = [1 2 3 ; 4 5 6; 7 8 9];
b=[5 5 5];  
a( end+1, : ) = b; 

or

a( :, end+1 ) = b'; 

[Lan]

thank you, it helps.