How to combine multiple numbers into 1 number?

I have the numbers R1, R2, Zr1, that I want to fuse together into 24000 . Zr1 is an array, while R1 and R2 are double. I have tried strcat but it only produces 240 0 0 which is not the intended 24000

R1 = 2

R2 = 4

Zr1 = 0 0 0

[Stephen23]

"Zr1 is an array, while R1 and R2 are double"

All doubles are arrays. Scalars are not a separate type, because in MATLAB everything is an array:

https://www.mathworks.com/help/matlab/matlab_prog/fundamental-matlab-classes.html

Answer 1

[Stephen23]

General solution:

R1 = 2;
R2 = 4;
Zr1 = [0,0,0];
V = [R1,R2,Zr1];
N = 10.^(numel(V)-1:-1:0) * V(:)

N = 24000

[Hieu]

Thanks Stephen! If you don't mind, can you explain how N = 10.^(numel(V)-1:-1:0) * V(:) works?

[Steven Lord]

Since we're doing this numerically, another way to perform that last line is to think of V as a polynomial and evaluate that polynomial at x = 10.

R1 = 2;
R2 = 4;
Zr1 = [0,0,0];
V = [R1,R2,Zr1]

V = 1×5

2 4 0 0 0

N = 10.^(numel(V)-1:-1:0) * V(:)

N = 24000

N2 = polyval(V, 10)

N2 = 24000

syms x
polynomial = x.^(numel(V)-1:-1:0)*V(:)

polynomial = 

N3 = subs(polynomial, x, 10)

N3 = 

24000

N4 = V(1)*1e4 + V(2)*1e3 + V(3)*1e2 + V(4)*1e1 + V(5)*1e0

N4 = 24000

N5 = V(1)*10^4 + V(2)*10^3 + V(3)*10^2 + V(4)*10^1 + V(5)*10^0

N5 = 24000

[Stephen23]

"can you explain how N = 10.^(numel(V)-1:-1:0) * V(:) works?"

Break code down to know how it works. You can do this yourself.

R1 = 2;
R2 = 4;
Zr1 = [0,0,0];
V = [R1,R2,Zr1] % so V is a 1x5 vector: [10000's,1000's,100's,10's,1's]

V = 1×5

2 4 0 0 0

Clearly all we need to do is to multiply the elements of V by the corresponding power of ten, and then add them together. Note that [10000,1000,100,10,1] is just [1e4,1e3,1e2,1e1,1e0] which is just 10.^[4,3,2,1,0]. So that is very easy to generate:

P = numel(V)-1:-1:0

P = 1×5

4 3 2 1 0

Q = 10.^P

Q = 1×5

10000 1000 100 10 1

Then one simple matrix multiplication does both the multiplying and the addition:

Q * V(:)

ans = 24000

https://en.wikipedia.org/wiki/Matrix_multiplication

[Steven Lord]

Another way to generate the Q vector is with logspace.

Q = logspace(4, 0, 5)

Q = 1×5

10000 1000 100 10 1

Answer 2

[Alan Stevens]

Do you mean

R1 = 2; R2 = 4; Zr1 = [0 0 0];
R = R1*10^4+R2*10^3+Zr1(1)*10^2+Zr1(2)*10+Zr1(3)

R = 24000

Alternatively:

R1 = 2; R2 = 4; Zr1 = [0 0 0];
R = [R1, R2, Zr1]

R = 1×5

2 4 0 0 0

M = 10.^[4 3 2 1 0]

M = 1×5

10000 1000 100 10 1

R = M*R'

R = 24000