# How to link two arrays?

1 view (last 30 days)
Meshooo on 30 Jan 2017
Commented: Meshooo on 31 Jan 2017
Dear all,
I have two arrays:
A = [1,2,3,4,5,6,7,8,9,10];
B = [11,12,13,14,15,16,17,18,19,20];
If A became New_A = [4,3,2,1,10,9,8,7,6,5];
Then how to apply the same change to B such that
New_B = [14,13,12,11,20,19,18,17,16,15].
Any help will be appreciated.
Meshoo

Stephen23 on 30 Jan 2017
Edited: Stephen23 on 30 Jan 2017
Assuming that the elements are unique, then ismember will work:
>> A = [1,2,3,4,5,6,7,8,9,10];
>> B = [11,12,13,14,15,16,17,18,19,20];
>> New_A = [4,3,2,1,10,9,8,7,6,5];
>> [~,idx] = ismember(New_A,A);
>> New_B = B(idx)
New_B =
14 13 12 11 20 19 18 17 16 15
Meshooo on 31 Jan 2017
Thank you very much.

Jan on 30 Jan 2017
If A contains the sorted numbers from 1 to n as in your example, the solution is easy:
B_new = B(A_new);
But maybe this matters the example data for the forum only.
Meshooo on 31 Jan 2017
Thank you Jan. Yeah I have more complex situations and it is not always serial numbers.

### Categories

Find more on Characters and Strings in Help Center and File Exchange

### Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!