How can we insert a row matrix without altering the rest of the values?

Hi!

Say, I have this matrix -

A = 
     1     2     3
     4     5     6
     7     8     9
    10    11    12
    13    14    15

Now I want to add A*10 after each of the rows so that I can make this matrix -

A = 
     1     2     3
     10    20    30
     4     5     6
     40    50    60
     7     8     9
     70    80    90
    10    11    12
    100   110   120
    13    14    15
    130   140   150

I have hundreds of rows, so I would prefer a loop (or anything!)

Thank you for your help.

Answer 1

[Dyuman Joshi]

A = reshape(1:15,3,5)'

A = 5×3

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

%pre-allocation
y=zeros(size(A,1)*2,size(A,2));
y(1:2:end,:)=A;
y(2:2:end,:)=A*10

y = 10×3

1 2 3 10 20 30 4 5 6 40 50 60 7 8 9 70 80 90 10 11 12 100 110 120 13 14 15 130 140 150

[Ashfaq Ahmed]

You are very intelligent! The algorithm is awesome!

Answer 2

[Fangjun Jiang]

A=magic(3);
C=transpose(reshape([A,10*A]',size(A,1),[]))

C = 6×3

8 1 6 80 10 60 3 5 7 30 50 70 4 9 2 40 90 20