MATLAB: Remove consecutive duplicates from matrix

Question

Hello,

i need to remove duplicates form my matrix, but only if they are consecutive duplicates.

Lets suppose i have the following list of coordinates in a matrix, with for example x, y and z coordinates, that is describing a path.

A=[ 1, 0, 3
    2, 1, 3
    2, 1, 3
    2, 2, 3
    1, 0, 3]

Now, you can see that the point [2, 1, 3] is a consecutive duplicate, that I want to remove (because it's unuseful information).

But I do not want to remove the (duplicate) row at the end, [1, 0, 3], even if this row is already there in the beginning.

Also, the sorting shouldn't be changed. The desired output should be

A=[ 1, 0, 3
    2, 1, 3
    2, 2, 3
    1, 0, 3]

I cannot use 'unique' for that, because that would filter also the last line.

What is the smartest way to do that?

Thank you very much for your help!

Answer 1

Try this

A=[ 1, 0, 3
    2, 1, 3
    2, 1, 3
    2, 2, 3
    1, 0, 3];
idx = find(~any(diff(A), 2))+1;
A(idx, :) = [];