Hi all! Is there a way to initialize row vectors like this:

R1= x1; G1= x2; B1= x3; R2= x4; G2= x5; B2= x6; R3= x7; G3= x8; B3= x9; And so on Please help!

[Shounak Shastri]

Is x a matrix with x1, x2,..., xn being rows of x?

[Huma Jabeen]

No, it's a single row vector.

[Stephen23]

Why split them up? MATLAB works best when you keep data together as much as possible.

Just use indexing: indexing is simple, neat, easy to debug, and very efficient. The best solution is to use one array right from the very start, so that you can write simpler, more efficient code, and not to make copies of your data and make it harder to work with.

You should read this:

https://www.mathworks.com/matlabcentral/answers/304528-tutorial-why-variables-should-not-be-named-dynamically-eval

It is possible to do what you asked for, but the MATLAB documentation states: "A frequent use of the eval function is to create sets of variables such as A1, A2, ..., An, but this approach does not use the array processing power of MATLAB and is not recommended. The preferred method is to store related data in a single array"

source: https://www.mathworks.com/help/matlab/matlab_prog/string-evaluation.html

Answer 1

[Shounak Shastri]

"No, it's a single row vector."

Based on this I will assume that R,G and B are also row vectors.

Say,

 x=1:30

You can divide elements in x as

 R=x(1:3:end-2);
 G=x(2:3:end-1);
 B=x(3:3:end);

This will give you R, G, B as row vectors with elements from x.

Answer 2

[Birdman]

There are several ways to do it. For instance, you can symbolically initialize a row vector as

>>x=sym('R',[1 9]);

x =

[ R1, R2, ..., R9]

or you may use str2sym function if you have R2017b version.

>>x=["R1","R2","R3",...,"R9"];
str2sym(x)

x =

[ R1, R2, ..., R9]

or by using a for loop, you can do it as follows:

x=sym(zeros(1,9));
for i=1:numel(x)
    x(i)=sym(sprintf('R%i',i));
end

Hope this helps.

[Shounak Shastri]

for loop wins my vote.