Clear Filters
Clear Filters

How do you append to a matrix within a for loop?

275 views (last 30 days)
Hi, I am using a for loop to process data (this part works fine). What I need to do is take the matrix (A) and after each loop update A to create one matrix. For instance, in the image below A is produced on the first loop, during loop 2 A "grows" to include the data from loop 1 and the data from loop 2, and so on.
Loop 1 produces a matrix, on the next iteration I need to append to this matrix the results of that loop, and so on until all of the data is processed.
It should be noted that the number of rows on each loop is unknown. However, the number of columns is fixed to 7.
Any ideas would be greatly appreciated please.

Accepted Answer

José-Luis
José-Luis on 8 Jul 2016
Edited: José-Luis on 8 Jul 2016
your_result = [];
for ii = whatever
some_vector = some_function(of_something);
your_result = [your_result; {some_vector}];
end
  8 Comments

Sign in to comment.

More Answers (2)

Azzi Abdelmalek
Azzi Abdelmalek on 8 Jul 2016
A=[1 2;3 4]
B=[4 5;6 7]
A=[A;B]
  1 Comment
chels19
chels19 on 8 Jul 2016
Thank you but this just replaces the data within the loop. I need to update A on every iteration so that it grows.

Sign in to comment.


SRIAKILAN S A
SRIAKILAN S A on 21 Feb 2023
% make an empty array
% the main command is end+1
N=[];
for i=0:10
x=i*i;
N(end+1)=[x]
end
N = 0
N = 1×2
0 1
N = 1×3
0 1 4
N = 1×4
0 1 4 9
N = 1×5
0 1 4 9 16
N = 1×6
0 1 4 9 16 25
N = 1×7
0 1 4 9 16 25 36
N = 1×8
0 1 4 9 16 25 36 49
N = 1×9
0 1 4 9 16 25 36 49 64
N = 1×10
0 1 4 9 16 25 36 49 64 81
N = 1×11
0 1 4 9 16 25 36 49 64 81 100

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!