How to campare index number of a matrix with other

I have two array. A=[ 9 8 5 4 4 10] and B=[1 1 1 3 3 3 2 2 1 1]. Now, I want to campare A and B. The index number of each element in matrix B is same in matrix A. I want to represent the matrix A by the value of matrix B as its index number is same with. Now I want to represent matrix A as like B i.e. A will be A=[1 2 3 3 3 1]. How will write it code.

Answer 1

[Raj]

for i=1:numel(A)
A(i)=B(A(i));
end

Also please see this.

[AS]

Thank you..

[Rik]

You are not taking advantage of the array processing abilities of Matlab. This loop is unnecessary. For such a small example the difference between a loop and array calculations will be small, but especially for larger arrays the difference in performance will start adding up.

[Raj]

Agreed but here the user is new to matlab and the 'for loop' code gives a better understanding of what is happening in the background. The solution is for this particular problem statement only and even I won't recommend using loops for large martices.

[Rik]

I think it is better to learn complex syntax with small examples. Especially for new users it is important to not resort to loops. Here it is easy to see how to avoid loops, so pausing to consider how to avoid a loop is a useful exercise. Learn it when it doesn't matter so you can apply it when it does.

[Stephen23]

"...the 'for loop' code gives a better understanding of what is happening in the background.

I disagree: MATLAB is a high-level language and array indexing is one of its most powerful features. Learning how to use array indexing is not more complex than a loop: Riks solution is simpler than this answer and more efficient.

Array indexing is required for any user who wants to learn how to use MATLAB effectively.

[AS]

Agree

Answer 2

[Rik]

A=[ 9 8 5 4 4 10];
B=[1 1 1 3 3 3 2 2 1 1];

newA=B(A);

[AS]

its better than previous one