[A,b] = equationsT​oMatrix(eq​ns,vars), large amount of vars

I want to use the function

[A,b] = equationsToMatrix(eqns,vars)

Where vars is [A1, A2, A3, A4, ... An], is there a way to do this automatically without typing out every variable up to An?

Answer 1

[Star Strider]

I would make ‘A’ a vector (or matrix). Then:

A = [A1 A2 ... An];

You can pass it simply as ‘A’. You can recover its elements as necessary as A(1)...A(n) The exact assignments vary if ‘A’ is a matrix instead of a vector.

I can’t be more specific than that with what you have presented in your Question.

[Jeffrey]

Thank you for the answer.

But doesn't that also require typing out A1 A2 A3.. up to An? The part I'm having trouble with is I don't want to type up a large number of variable names. Surely there's a way to list A1 up to say A100, without typing out every thing in between?

[Star Strider]

If A1 ... An already exist in your workspace, you can use eval and a loop to convert them into a vector:

A1 = 1;  A2 = 3;  A3 = 5;  A4 = 7;  A5 = 9;

for k1 = 1:5
    A(k1) = eval(sprintf('A%d', k1));
end

If you then display A, you will see that it contains the values of A1 ... A5 here, or as many as you need it to contain in your applicaiton. The loop will completely take care of the conversion.

[Jeffrey]

That worked really well. Thanks!

[Star Strider]

My pleasure!