# How to merge matrix in a loop?

2 views (last 30 days)
Akshay Sahu on 28 Oct 2022
Commented: Akshay Sahu on 29 Oct 2022
Suppose I have four matrix
A,B,C and D. These all are (mx3) matrix where m is some number.
and I have to define a number as an user input which is N.
Now I want a merge matrix such that,
for N = 1
New_matrix = [A]
for N = 2
New_matrix = [A
B
C]
for N = 3
New_matrix = [A
B
C
D
A]
for N = 4
New_matrix = [A
B
C
D
A
B
C]
and so on......

David Hill on 28 Oct 2022
A=randi(10,4,3)
A = 4×3
10 2 9 7 7 4 10 5 1 5 9 2
B=randi(10,5,3)
B = 5×3
8 6 1 10 1 9 6 5 9 5 8 8 10 3 3
C=randi(10,6,3)
C = 6×3
1 6 4 9 4 2 7 5 6 9 5 4 3 2 5 1 2 7
D=randi(10,7,3)
D = 7×3
5 8 3 4 9 5 5 3 9 6 7 7 4 9 3 8 5 6 7 9 9
N=2;
newMatrix=generateMatrix(A,B,C,D,N)
newMatrix = 15×3
10 2 9 7 7 4 10 5 1 5 9 2 8 6 1 10 1 9 6 5 9 5 8 8 10 3 3 1 6 4
function newMatrix=generateMatrix(A,B,C,D,N)
n=2*N-1;
s=[size(A,1),size(B,1),size(C,1),size(D,1)];
newMatrix=repmat([A;B;C;D],ceil(n/4),1);
S=sum(s*floor(n/4))+sum(s(1:mod(n,4)));
newMatrix=newMatrix(1:S,:);
end
Akshay Sahu on 29 Oct 2022
Thank you @David Hill, your algorithm worked as I want.

KALYAN ACHARJYA on 28 Oct 2022
Edited: KALYAN ACHARJYA on 28 Oct 2022
% Just example
A=rand(4,3);
B=rand(4,3);
C=rand(4,3);
D=rand(4,3);
data_mat={A,B,C,D}; % Created to handle data easily
N=4 ; % Example or length of data_mat
data=cell(1,N); %Memory Pre-allocation
for i=1:N
data{i}=horzcat(data_mat{1:i});
end
data
data = 1×4 cell array
{4×3 double} {4×6 double} {4×9 double} {4×12 double}
You may look for cellfun also, please do the modification as per requirements.
##### 2 CommentsShow 1 older commentHide 1 older comment
Akshay Sahu on 29 Oct 2022
Yes, It's also correct for N=4. But N is not constant in my case. I want to change value of N according to my need.

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