delete row in matrix if value in another matrix is unique

Hi,

probably a simple question, but I need your help.

I have 2 matrices with 1 column each. Values ​​appear twice in the first matrix (x1). I select this with unique and delete it. In the 2nd matrix (y1) I want to delete the same row as in matrix 1. So e.g. Row 12 contains twice the value and is deleted, then row 12 in the other matrix should also be deleted after that they should contain the same number of values.

The two matrices are attached

Thank you very much

Answer 1

[Jonas]

you want to delete entries when the number is repeated first?

firstVec=[5 3 5 1 7 9 3 1 4];

secVector=1:numel(firstVec)

secVector = 1×9

1 2 3 4 5 6 7 8 9

[~,firstOnly]=unique(firstVec,'stable')

firstOnly = 6×1

1 2 4 5 6 9

% keep only entries at first number occurence
secVector(firstOnly)

ans = 1×6

1 2 4 5 6 9