Replacing same rows with same variables in first to third column

2 vues (au cours des 30 derniers jours)
mr mo
mr mo le 21 Déc 2017
Commenté : Stephen23 le 21 Déc 2017
Hi. I have two matrices named aa and m.
aa=[1 2 3 7
4 5 6 8
7 8 9 9
3 2 3 8
6 5 6 7
7 8 7 9];
mm=[1 2 3 5
4 5 6 9
7 8 9 6];
I want to replace the rows of aa with the rows of m that have the same values in first to third column.
How can I do that?
Thanks a lot.
  2 commentaires
Image Analyst
Image Analyst le 21 Déc 2017
What if m is
mm=[1 2 3 5
1 2 3 9
4 5 6 9
7 8 9 6];
Which row of m, the first or the second, should replace the first row of aa?
mr mo
mr mo le 21 Déc 2017
In my case there are only one same rows in ‘aa’ and ‘mm’

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Réponses (2)

Jos (10584)
Jos (10584) le 21 Déc 2017
No need for loops at all! Use both outputs of ismember and replace accordingly
aa = [1 2 3 7
4 5 6 8
7 8 9 9
3 2 3 8
6 5 6 7
7 8 7 9
1 2 3 999];
mm = [1 2 3 5
4 5 6 9
7 8 9 6];
[tf,loc] = ismember(aa(:,1:3),mm(:,1:3),'rows')
% tf indicates which rows in aa are found where (loc) in mm (only for columns 1-3)
aa(tf,:) = mm(loc(tf),:) % replace those rows

KSSV
KSSV le 21 Déc 2017
Modifié(e) : KSSV le 21 Déc 2017
aa(1:3,1:3) = mm(1:3,1:3) ;
  1 commentaire
mr mo
mr mo le 21 Déc 2017
Thanks but this codes lost the fourth column values of mm.

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