How to make comparison between paired elements?

Hi, I would like to compare pair of adjacent elements of array. For example:

if 
  A=[1;
     2;
     1;
     3;
     2;
     4]

In this case the pairs are (1 2) (1 3) (2 4)... So in this case I have "unique" pairs.

But for example:

    A=[1;
       2;
       1;
       2;
       2;
       4]

In this case the pairs are (1 2) (1 2) (2 4) .... In this case I don't have "unique" pairs.

How can I make the comparisson of pairs, considering the pair is form with the adjacent element.

thanks

Answer 1

[Star Strider]

A=[1;
       2;
       1;
       2;
       2;
       4]

Ar = reshape(A, 2, [])';
UA = unique(Ar,'rows')

The ‘UA’ matrix rows are the unique adjacent elements of your ‘A’ vector.

[Patty]

But, for example... If I have the matrix

A=[1;2;2;1;3;4]

The pairs are (1 2) (2 1) (3 4) .... In this case the first and second pair are considered the same because both has the same elements inside, it doesnt matter that is different position.

[arich82]

Rehsape to Ar as shown, then sort your rows before applying unique:

   A=[1;
       2;
       2;
       1;
       3;
       4];
Ar = reshape(A, 2, [])';
Ars = sort(Ar, 2);
UA = unique(Ars,'rows')

[Patty]

I got it using your suggestions... Thanks so much!.. Just a little change.

    D=reshape(A,2,[]);
    F=sum(D);
    anyRepeated = length(unique(F) < length(F));
    if anyRepeated<length(F)
        passFlag2=0;
    else
        passFlag2=1;
    end

I just copied here, in case somebody else needed.. :)

[Star Strider]

My pleasure!

And thank you arich82.