# Modify Repmat function to concatenate array

2 views (last 30 days)
Santos García Rosado on 9 Feb 2021
Hello MathWorks community.
I'm trying to concatenate an array of my own "n" times. The thing is that each time each time I concatenate the array, I want to multiply it by 1, 10, 20...
For example, lets say my initial array is [0,1,2,3,4]. And that n =3. Then the output should look like:
out = [0,1,2,3,4,0,10,20,30,40,0,20,40,60,80]
I was wondering if I could use the repmat fucntion in some way to get this don, or is this function only useful for concatanating the exact same array?
Thank's for the help!
Santos

Stephen23 on 9 Feb 2021
V = [0,1,2,3,4];
n = 3;
X = [1,10*(1:n-1)];
Z = kron(X,V)
Z = 1×15
0 1 2 3 4 0 10 20 30 40 0 20 40 60 80
Santos García Rosado on 9 Feb 2021
Didn't know about that function. Thank you Stephen.

Monika Jaskolka on 9 Feb 2021
If you want to understand how repmat works, take a look at the syntax and description in the documentation page: https://www.mathworks.com/help/matlab/ref/repmat.html.
I was able to do this using a loop:
n = 3;
init = [0, 1, 2, 3, 4];
out = init;
for i = 1:n-1
factor = 10*i;
out = horzcat(out, init.*factor);
end
Santos García Rosado on 9 Feb 2021
Thank's Monika, the loop works aswell. I've read the documentation but still acan't figure out a way.

### Categories

Find more on Loops and Conditional Statements in Help Center and File Exchange

### Community Treasure Hunt

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

Start Hunting!