Could you help me solving the question regarding to coordinates, please?

Let's say I have such points:

• A=(2,4)
• B=(2,10)
• C=(2,15)
• D=(5,14)
• E=(6,7)
• F=(6,15)
• G=(8,16)
• H=(8,10)and I just want to select unique points which are A,B,C,D,E and G. I want to eliminate F and H because I've already used 6 in E and 15 in C for F; 8 in G and 10 in B.

Thanks for your time!

[Patrik Ek]

Ok you mean so that you can perform operations like,?

M(allSelectedPoints) = 42;

[Rengin]

I just want to select/see the points (A,B,C,D,E and G)eliminating F and H. Is there any way to do that?

Answer 1

[Mischa Kim]

Rengin, use

 data = [2,4;
         2,10;
         2,15;
         5,14;
         6,7;
         6,15;
         8,16;
         8,10]; 
 [C,ia,ic] = unique(data(:,2));
 data_elim = sortrows(data(ia,:),1)

Addendum: the below snippet shows how to read from and write to an Excel file.

 data = xlsread('test.xlsx',1);       % read from sheet 1
 [C,ia,ic] = unique(data(:,2));
 data_elim = sortrows(data(ia,:),1);
 xlswrite('test.xlsx',data_elim,2);   % write to sheet 2

[Rengin]

I am sending my data file as excel with what I want to see and results after your recommendation. I cannot get some elements which I want to see. I filled some of them with yellow as examples. Why do I meet such a problem?

Thank you for your help.

[Image Analyst]

You forgot to attach your workbook. Also, please be aware of the FAQ when comparing floating point numbers instead of integers: http://matlab.wikia.com/wiki/FAQ#Why_is_0.3_-_0.2_-_0.1_.28or_similar.29_not_equal_to_zero.3F

[Mischa Kim]

I see. This one produces the result you're looking for:

 data_elim = data;
 for ii = 2:length(data(:,1))
    if sum(ismember(data(ii,:),data(1:ii-1,:))) == 2
        data_elim(ii,:) = [NaN NaN];
    end
 end
 data_elim(all(isnan(data_elim(:,1)),2),:) = [];

[Rengin]

Thank you so much Mischa!