CODEWITHSUNDEEP
matlab
Jellyse
Jellyse

Reputation: 863

Linking and sorting two arrays

I want to link, join and sort two arrays that are linked to another two arrays, like so:

A1 = [5, 4, 8, 6] linked to

A2 =[10, 15, 12, 14] and

B1= [5.5, 6.5, 8.5, 4.5] linked to

B2=[11.5, 25.5, 16.5, 49.5]

I want to join A1 with B1 into C1 and A2 with B2 into C2 and when I sort C1, C2's numbers should move with the numbers of C1, since they are linked. More clearly:

C1=[5, 4, 8, 6, 5.5, 6.5, 8.5, 4.5] 
C2=[10, 15, 12, 14, 11.5, 25.5, 16.5, 49.5]

D1=[4, 4.5, 5, 5.5, 6, 6.5, 8, 8.5 ] % sorted C1
D2 = [15, 49.5, 10, 11.5, 14, 25.5, 12, 16.5 ] % since 4 is linked to 15, 4.5 is linked to 49.5 etc...

I am actually trying to do in matlab what is very simple in excel, you have two columns, sort one and the other follows.

Here's what I tried so far:

C1=[A1, B1];%join them
C2=[A2, B2];

D=[C1;C2];
D1=sort(D(1,:)); % this does not work

I think I have to use find somewhere, but I don't know how.

Upvotes: 1

Views: 56

Answers (1)

HansHirse
HansHirse

Reputation: 18905

Using sort was the right idea. You can obtain the indices of the sorted array by getting the second return value, see the documentation on sort.

So, the quite simple solution should be:

D = [C1; C2];         % Build D
[~, idx] = sort(C1);  % Sort C1, but only use the indices of the sorted C1
D = D(:, idx)         % Rearrange D column-wise by the sorted indices

D =
    4.0000    4.5000    5.0000    5.5000    6.0000    6.5000    8.0000    8.5000
   15.0000   49.5000   10.0000   11.5000   14.0000   25.5000   12.0000   16.5000

Upvotes: 3

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