Remove corresponding values in two arrays

Hi!

I have a vector with a lot of numbers, for example A = [9,1,5,2,3,2] and B = [12,23,41,4,10,6] (for example) and I want to remove all the values that are different from 1,2,5 or 9 and the correspondent elements in B. In this case I would want to remove the 3 in A and the 10 in B, ending uo with: new_A = [9,1,5,2,2] and new_B = [12,23,41,4,6]. For removing the values in A I'm doing the following but I dont know how to do remove the elenments in B.

(I want to apply this to vectors with hundreds of values so I cannot remove that separately)

A = [9,1,5,2,3,2] ;
B = [12,23,41,4,10,6];

x = [1,2,5,9,]; % values to keep in A
new_A = A(ismemmber(A,x)); 

How can I do this easily?

[Adam Danz]

This is the same question you asked in another thread:

https://www.mathworks.com/matlabcentral/answers/801376-remove-specific-values-from-array#comment_1459341

Answer 1

[David Hill]

A = [9,1,5,2,3,2] ;
B = [12,23,41,4,10,6];
x = [1,2,5,9,]; % values to keep in A
new_A = A(ismember(A,x)); 
new_B = B(ismember(A,x));

[Ana Gabriela Guedes]

thank you a lot!! It works just like that :)

Answer 2

[Bob Thompson]

How can I do this easily?

Please feel free to elaborate what 'easily' means to you. Your logic for A seems pretty well set up to me. The only thing I can think of to make it more 'easy' would be how you're generating x, but I know nothing about that, so I can't help.

That said, getting B to be reduced is actually just as simple.

new_B = B(ismember(A,x));

The same logic for A can be applied to B because ismember(A,x) produces a logic array, rather than the specific values, and so you can similarly using it to indicate which elements of B you want.

This does require A and B to be the same size (I believe).

[Ana Gabriela Guedes]

thank you a lot!! It works just like that :)